WEEDS 

OF  FARM  LAND 


W.  E.  BRENCHLEY 


WEEDS  OF  FARM  LAND 


. 


FIG.  31. — RED  BARTSIA  (Bartsia  odontites),  parasitic  on  Wheat. 


WEEDS 
OF   FARM    LAND 


WINIFRED  E.  BRENCHLEY,  D.Sc,  F.L.S. 

\\ 

FELLOW  OF    UNIVERSITY   COLLEGE,    LONDON 
BOTANIST,   ROTHAMSTED   EXPERIMENTAL  STATION 


WITH  ILLUSTRATIONS 


LONGMANS,    GREEN    AND    CO. 

39     PATERNOSTER     ROW,     LONDON 

FOURTH  AVENUE  &  30TH  STREET,  NEW  YORK 
BOMBAY,    CALCUTTA,    AND    MADRAS 

1920 


\oA 


PREFACE. 

EVERYONE  who  cultivates  the  soil,  whether  on  the  farm 
or  garden,  is  perforce  interested  in  weeds,  for  their 
absence  or  presence  amongst  the  crops  has  much  to  do 
in  determining  the  relative  success  or  failure  of  the 
undertaking.  A  very  great  deal  has  been  written  on 
the  subject,  but  the  information  is  widely  scattered 
throughout  the  literature  of  agriculture  and  botany.  In 
this  country,  at  least,  very  few  efforts  have  hitherto 
been  made  to  gather  up  and  correlate  this  varied  know- 
ledge, thus  rendering  it  accessible  to  those  most  inter- 
ested. Furthermore,  it  is  only  of  recent  years  that 
definite  attempts  have  been  made  to  work  out  the  quanti- 
tative and  qualitative  relations  between  weeds,  the  soils 
on  which  they  grow  and  the  crops  with  which  they  are 
associated.  In  this  respect  the  conclusions  so  far  drawn 
can  only  be  regarded  as  tentative,  subject  to  modification 
and  revision  as  more  data  become  available.  It  has 
seemed  justifiable,  therefore,  to  attempt  to  set  forth  the 
present  position  of  affairs,  in  order  that  future  attacks  on 
the  weed  problem  may  be  more  co-ordinated,  and  that 
valuable  time  and  labour  may  be  utilised  to  the  best 
advantage. 

The  original  investigations  embodied  in  the  follow- 
ing pages  owe  much  to  the  cordial  assistance  afforded 
by  the  many  landowners  and  farmers  whose  land  has 
been  utilised  for  the  purpose.  It  is  impossible  to  record 
each  individually,  but  my  special  thanks  are  due  to  Pro- 
fessor T.  B.  Wood,  Mr.  Spencer  Pickering,  Mr.  E.  S. 
Beaven,  Mr.  E.  E.  Stokes,  and  Mr.  J.  H.  Burton,  all 


470438 


vi  PREFACE 

of  whom  facilitated  the  work  by  giving  me  introductions 
throughout  the  districts  with  which  they  were  best  ac- 
quainted. 

Miss  M.  B.  Lee  and  Miss  V.  G.  Jackson  have 
rendered  valuable  assistance  with  the  proof  sheets,  and, 
above  all,  I  am  specially  indebted  to  Dr.  E.  J.  Russell 
for  his  constant  advice  and  criticism  throughout  the  pre- 
paration of  the  book. 

W.  E.  B. 

ROTHAMSTED, 

June,  1920. 


CONTENTS. 


CHAPTER  I. 
INTRODUCTION 


CHAPTER  II. 
DISTRIBUTION  OF  WEEDS 10 

CHAPTER  III. 
PREVENTION  AND  ERADICATION  OF  WEEDS       -        -        -        -        -        -      43 

CHAPTER  IV. 
VITALITY  OF  WEED  SEEDS -        -        -  72 

CHAPTER  V. 
HABITS  OF  WEEDS 84 

CHAPTER  VI. 
PARASITIC  WEEDS 92 

CHAPTER  VII. 
POISONOUS  AND  INJURIOUS  WEEDS IO3 

CHAPTER  VIII. 
ARABLE  WEEDS.    ASSOCIATION  WITH  SOILS.     I.  GENERAL     -        -        -     "7 

CHAPTER  IX. 
ARABLE  WEEDS.     ASSOCIATION  WITH  SOILS.     II.  SPECIAL      -        -        -     121 


viii  CONTENTS 

PAGE 

CHAPTER  X. 
ARABLE  WEEDS.     ASSOCIATION  WITH  CROPS 159 

CHAPTER  XI. 
GRASSLAND  WEEDS 175 

CHAPTER  XII. 
USES  OF  WEEDS 187 

CHAPTER  XIII. 
POPULAR  AND  LOCAL  NAMES  OF  WEEDS          ....  .    206 


LIST   OF    ILLUSTRATIONS. 


FIG. 


31.     RED  BARTSIA  (Bartsia  odontites),  parasitic  on  Wheat         -       Frontispiece 

PAGE 

1.  BLACK  BENT  (Alopecurus  agrestis) 8 

2.  FAT  HEN  (Chenopodium  album) 13 

3.  ORACHE  (Atriplex  patuld) 14 

4.  SPIKELET  OF  FRUITS  OF  WILD  OAT  (Avenafatua)  16 

5.  KNOTGRASS  (Polygonum  aviculare) 19 

6.  FRUIT  OF  NARROW-LEAVED  VETCH  (Vicia  angustifolia)  21 

7.  A.  WINGED  SEED  OF  YELLOW  RATTLE  (Rhinanthus  crista-galli)    -  22 

B.  WINGED  SEED  OF  SPURRY  (Spergula  arvensis)  22 

C.  WINGED  FRUIT  OF  HOGWEED  (Heracleum  sphondylium)     -        -  22 

D.  WINGED  FRUIT  OF  BROAD-LEAVED  DOCK  (Rumex  obtusifolius)    -  22 

8.  PLUMED  FRUITS — 

A.  Coltsfoot  (Tussilago  farfara) 24 

B.  Creeping  Thistle  (Cirsium  arvense)  -        -        -        -        -        -  24 

C.  Hawkbit  (Leontodon  hispidus) 24 

D.  Dandelion  (Taraxacum  vulgar  e) 24 

E.  Groundsel  (Senecio  vulgaris) 24 

F.  Goatsbeard  (Tragapogon  pratensis) 24 

9.  PLUMED  SEEDS  OF  WILLOW-HERB  (Epilobium  sp.)  -        -        -        -  25 
10.     HOOKED  FRUITS — 

A.  Agrimony  (Agrimonia  eupatoria) 26 

B.  Wild  Carrot  (Daucus  carota)    -        -        -        -        -        -        -  26 

C.  Goosegrass  (Galium  aparine) 26 

D.  Corn  Buttercup  (Ranunculus  arvensis)     -        -        -        -        -26 
n.     CORN  BUTTERCUP  (Ranunculus  arvensis) 27 

12.  SHEPHERD'S  NEEDLE  (Scandix  pecten) 28 

13.  BINDWEED  (Convolvulus  arvensis)      -         -        -        -        -        -        -29 

14.  CREEPING  THISTLE  (Cirsium  arvense) 3° 

15.  HORSETAIL  (Equisetum  arvense) 31 

16.  COUCH-GRASS  (Agropyron  repens) 32 

17.  CORN  SOWTHISTLE  (Sonchus  arvensis) 33 

18.  COLTSFOOT  (Tussilago  farfara) 34 

19.  WOODWAX  (Gtnista  tinctoria) 35 

20.  SORREL  (Rumex  acetosa) 3^ 

ix 


x  LIST  OF  ILLUSTRATIONS 

PIG.  PAGE 

21.  BULBOUS  BUTTERCUP  (Ranunculus  bulbosus) 37 

22.  MOUSE-EAR  HAWKWEED  (Hieradum  pilosella)   -        -        -     *  •        -  39 

23.  CREEPING  BUTTERCUP  (Ranunculus  repens) 4° 

24.  ONION  COUCH  (Arrhenatherum  avenaceum) 41 

25.  SEEDLING  OF  CREEPING  THISTLE  (Cirsium  arvense)  -        -        -        -  82 
36.     DODDER  (Cuscuta  trifolii),  parasitic  on  Clover    -  93 

27.  BROOMRAPE  (Orobdnche  minor),  parasitic  on  Sainfoin.     Right. — ^ 

Sainfoin  plant  not  attacked.   Left. — Sainfoin  plant  attacked  by  I    face 

broomrape,  showing  the  harmful  effect  on  growth        -        -   .  j  P-  9^ 

28.  BROOMRAPE  (Orobanche  minor),  parasitic  on  Lucerne  -        -         -     ' 

29.  YELLOW  RATTLE  (Rhinanthus  major),  parasitic  on  Oats    -         -        -  100 

30.  SECTION  ACROSS  BARLEY  ROOT  PENETRATED  BY  SUCKER  OF  YELLOW 

RATTLE  (Rhinanthus  major) 101 

32.  AUTUMN  CROCUS  (Colchicum  autumnale) 109 

33.  PURGING  FLAX  (Linum  catharticum) 109 

34.  CROW  GARLIC  (Allium  vineale) 113 

35.  RAMSONS  (Allium  ursinum)         -        - 113 

36.  SPURRY  (Spergula  arvensis)         -                                                    -        -  142 

37.  ANNUAL  KNAWEL  (Scleranthus  annuus) 143 

38.  SHEEP'S  SORREL  (Rumex  acetosella)  -        -                 ....  144 

39.  CORN  MARIGOLD  (Chrysanthemum  segetum) 145 

40.  QUAKER-GRASS  (Briza  media} 180 

41.  PLANTS  COMMON  IN  TRODDEN  PLACES — 

A.  Greater  Plantain  (Plantago  major) 184 

B.  Silverweed  (Potentilla  anserina)                                                    -  184 

C.  Rough-stalked  Meadow-grass  (Poa  trivialis)             -         -        -  184 


CHAPTER  I. 

INTRODUCTION. 

IT  is  impossible  to  begin  to  work  land  under  any  system  of 
farming  without  immediately  being  confronted  with  the  prob- 
lem of  weeds.  Weeds  are  the  inevitable  corollaries  of  crops, 
and  much  of  the  science  of  farming  consists  in  the  skilful  use 
of  methods  by  which  the  weeds  are  kept  in  subjection.  In 
the  ordinary  course  of  events  all  vacant  land  tends  to  clothe 
itself  with  vegetation,  and  soil  that  is  artificially  laid  bare 
during  farming  operations  offers  a  situation  that  is  most 
favourable  to  the  ingress  of  a  native  plant  population.  The 
farmer's  crops  are  more  or  less  alien  to  the  areas  on  which 
they  are  grown,  and  consequently  would  have  but  little  chance 
against  the  natural  colonists  if  it  were  not  for  the  assistance 
rendered  by  husbandry  methods.  Weeds  have  thus  a  very 
great  practical  and  economic  importance,  and  a  right  know- 
ledge of  their  habits  and  distribution  is  a  valuable  asset. 
Every  farmer  has  a  general  knowledge  of  the  worst  weeds 
that  occur  on  his  land,  and  usually  knows  how  to  deal 
with  them,  but  comparatively  few  have  that  special  know- 
ledge of  the  individual  weeds  which  is  necessary  if  the 
more  up-to-date  and  less-known  methods  of  prevention  and 
eradication  are  to  be  successfully  applied.  The  farmers  of 
this  country  are  in  possession  of  a  vast  amount  of  weed 
lore,  and  much  information  is  scattered  up  and  down  agri- 
cultural literature,  but  hitherto  very  little  attempt  has  been 
made  to  bring  together  the  facts  and  so  to  correlate  them 
that  they  form  a  complete  whole,  instead  of  being  merely 
disjointed  scraps  of  knowledge  of  local  interest  and  value 
only.  The  field  of  inquiry  is  so  large  and  the  difficulty  of 
obtaining  the  necessary  mass  of  information  so  great  that  it 
is  impossible  to  present  anything  like  a  perfect  picture  of  the 
weed  problem,  but  the  aim  of  the  present  book  is  to  sketch  a 
preliminary  outline  from  the  facts  that  are  already  available, 
in  the  hope  that  at  some  future  date  it  may  be  possible, 


2  "  WEED'S  *OF  'FARM  LAND 

in  the  light  of  fuller  knowledge,   to    fill    in  and    to    correct 
inaccuracies  in  the  details. 

Before  beginning  to  discuss  the  problem  in  its  general 
bearings  it  is  essential  that  one  should  have  a  clear  idea  ot 
the  meaning  of  the  term  weed.  The  word  is  used  very  loosely, 
and  under  some  circumstances  is  made  to  apply  to  almost  any 
plant  in  any  situation.  For  our  purpose,  however,  it  is 
essential  to  narrow  the  meaning  down  so  that  it  bears  an 
exact  significance.  British  farm-land  is  worked  on  two  distinct 
systems,  according  as  the  land  is  under  the  plough  or  laid 
down  to  grass.  Generally  both  systems  are  combined,  and  a 
typical  English  farm  consists  of  grass  and  arable  land  in  pro- 
portions which  vary  according  to  the  locality  and  to  the  in- 
dividual needs  of  the  farmer.  The  cropping  under  the  two 
systems  is  radically  different,  as  on  the  arable  land  the  crop 
plants  are  fugitive  and  occupy  the  soil  for  a  comparatively 
short  season  before  they  make  way  bodily  for  another  crop, 
whereas  on  grass-land  the  plants  are  permanent,  and  retain 
their  positions  year  after  year,  never  being  replaced  by  others 
unless  the  sward  is  ploughed  up  and  a  new  crop  sown.  This 
difference  in  cropping  has  so  great  an  influence  upon  the 
vegetation  that  covers  the  ground  that  it  is  necessary  to  have 
different  definitions  for  the  weeds  of  arabfe  and  grass-lands. 
On  ploughed  land  a  farmer  desires  only  the  crop  from  the 
seed  he  intends  to  sow,  and  anything  else  that  appears  on  the 
field  may  be  regarded  as  a  weed.  Consequently,  a  weed  of 
arable  land  may  be  defined  as  "  any  plant  other  than  the  crop 
sown ".  On  grass-land,  on  the  contrary,  a  varied  herbage 
is  desirable,  provided  that  the  constituents  of  the  herbage  are 
of  good  nutritive  value.  Old  pasture  is  usually  clothed  with 
a  mixture  of  grasses,  clover,  and  miscellaneous  plants,  which 
vary  in  proportion  and  in  their  value  as  food  for  stock  whether 
as  green  fodder  or  as  hay.  Some  of  the  grasses,  such  as 
Yorkshire  fog,  in  some  districts  are  almost  useless  or  are 
positively  harmful,  whereas  some  of  the  miscellaneous  plants 
such  as  rib-grass,  are  of  high  feeding  value  and  in  moderation 
are  welcomed  in  the  herbage.  It  is  thus  very  difficult  to  say 
exactly  what  constitutes  a  weed  of  grass-land,  but  perhaps  it 
may  be  defined  as  (a)  "a  plant  of  low  feeding  value,"  or  (fr) 
"  a  plant  that  grows  so  luxuriantly  or  plentifully  that  it  chokes 
out  other  plants  that  possess  more  valuable  nutritive  properties  ". 
Farmers  regard  the  weeds  of  ploughed  land  and  of  grass- 
land from  very  different  standpoints.  Every  agriculturist 


INTRODUCTION  3 

will  agree  that  alien  plants  among  arable  crops  are  pernicious 
and  should  be  got  rid  of  as  far  as  possible.  On  the  other 
hand,  the  weeds  of  grass-land  are  seldom  considered  to  be  of 
much  significance,  except  when  certain  plants  have  specially 
noxious  qualities  which  compel  the  farmers  to  take  measures 
against  them.  For  instance,  buttercups  are  rarely  eaten  by 
stock  if  plenty  of  other  food  is  available,  and  they  simply 
encumber  the  ground  when  present  in  large  quantities. 
Nevertheless,  nothing  is  done  to  get  rid  of  them  and  most 
people  regard  them  with  much  tolerance,  considering  them 
merely  as  signs  that  the  ground  is  particularly  fertile  where 
they  grow  luxuriantly.  If,  however,  a  little  garlic,  which 
taints  milk,  is  present  on  grazing  land  strong  measures  are 
taken  either  to  eradicate  it  or  to  ensure  that  milking  cows  do 
not  have  access  to  the  fields.  If  the  same  relative  quantities 
of  buttercups  and  garlic  were  present  on  arable  land,  the 
buttercups  would  be  even  more  harmful  than  the  garlic  in 
their  action  on  the  growth  of  the  crop,  and  every  effort  would 
be  made  to  rid  the  land  of  them.  Generally  speaking,  arable 
weeds  have  the  greater  practical  significance,  and  as  a  result 
much  more  information  is  available  with  regard  to  them  than 
is  the  case  with  pasture  weeds,  so  that  it  is  possible  to  draw 
more  definite  conclusions  as  to  their  occurrence. 

When  land  is  well  tilled  the  soil  is  constantly  disturbed 
by  such  operations  as  ploughing,  harrowing,  and  cultivating. 
After  a  crop  is  removed  the  soil  is  ploughed  up,  all  vegetation 
growing  on  it  is  buried  and  much  of  it  is  killed.  If  seeds  are 
buried  in  the  soil  they  may  germinate  after  the  first  ploughing, 
but  they  in  their  turn  are  destroyed  by  later  ploughing  or  by 
the  harrow  and  cultivator.  If  a  cereal  crop  is  grown  the  soil 
is  left  more  or  less  undisturbed  when  once  the  young  plants  are 
well  established,  but  if  roots  are  wanted  the  land  is  kept  culti- 
vated the  whole  time  the  crop  is  on  the  ground.  It  is  obvious 
that  these  conditions  are  not  at  all  favourable  to  the  persis- 
tence of  weed  plants  unless  they  are  so  specially  adapted  to 
hold  their  own  that  they  can  be  more  or  less  indifferent  to 
the  rough  treatment  they  get.  For  this  reason  the  number  of 
plant  species  that  occur  as  weeds  is  limited,  and  even  among 
this  number  there  are  very  many  which  very  seldom  occur, 
except  on  particular  soils  or  under  special  circumstances. 
There  are  few  species  that  are  really  prevalent  and  widespread, 
and  every  one  of  these  is  markedly  well  adapted  to  the  con- 
ditions of  life.  Furthermore,  the  weeds  that  are  ubiquitous  in 


4  WEEDS  OF  FARM  LAND 

this  country  are  chiefly  cosmopolitan,  and  they  either  occur 
naturally  under  arable  cultivation  in  other  countries  or  they 
colonise  rapidly  if  they  are  introduced.  In  parts  of  Australia 
the  bush  has  been  cleared  comparatively  recently  and  the  land 
brought  under  cultivation.  Where  this  has  occurred  the  native 
flora  has  disappeared  entirely,  being  unable  to  put  up  with  the 
interference  and  the  new  conditions,  but  a  weed  flora  has 
appeared  composed  of  species  that  are  common  as  weeds 
of  cultivation  in  America  and  the  Old  World.  The  introduced 
species  have  adopted  their  new  home  to  such  an  extent  that 
they  threaten  to  spread  in  a  most  injurious  fashion,  with  the 
result  that  legislation  has  been  brought  to  bear,  and  many  of 
the  more  common  species  are  proclaimed  as  noxious  weeds. 
Among  the  proclaimed  plants  of  Victoria  State  there  are 
several  that  have  been  introduced  from  other  parts  of  the 
world,  and  that  are  even  more  obnoxious  in  Australia  than 
they  are  in  this  country,  charlock,  dodder,  gorse,  hemlock,  and 
several  varieties  of  thistles,  as  the  milk  and  creeping  thistles, 
being  among  the  number. 

A  similar  thing  has  happened  in  Canada.  The  list  of 
Canadian  Farm  Weeds  l  consists  chiefly  of  species  that  have 
been  introduced  "from  Europe,  the  native  species  being  much 
less  in  evidence.  Wild  oat,  dock,  sheep's  sorrel,  spurry,  chick- 
weed,  corn  cockle,  buttercup,  shepherd's  purse,  charlock,  clover, 
dodder,  and  ribgrass  are  but  a  few  of  the  weeds  that  create  as 
much  trouble  in  Canada  as  they  do  in  England,  although  they 
are  not  indigenous  to  that  country  but  have  been  introduced  in 
the  course  of  cultivation.  The  same  story  is  told  by  collec- 
tions of  weed  seeds  that  have  been  sent  to  Rothamsted  from 
Tasmania  and  the  United  States,  and  it  is  evident  that  certain 
species  are  so  indifferent  to  the  wide  variation  of  soil  and 
climate  obtaining  in  different  parts  of  the  world  that  they  will 
colonise  and  spread  anywhere  under  conditions  of  cultivation. 

From  the  early  days  of  civilisation  the  weeds  or  alien  plants 
that  spring  up  among  cultivated  crops  have  attracted  much 
attention  because  of  the  direct  influence  they  exercise  on  the 
food  supply  of  mankind.  Methods  of  eradication  have1  been 
advocated  and  tested,  and  the  problem  considered  from  every 
side,  but  in  spite  of  all  that  has  been  done  the  weeds  still 
flourish  and  menace  the  well-being  of  the  crops  at  every  turn. 
It  is  impossible  to  do  away  with  weeds,  for  they  are  so  well 
equipped  for  holding  their  ground  and  reproducing  their 

1  Clark,  G.  H.,  and  Fletcher,  J.  (1909),  "  Farm  Weeds  of  Canada  ", 


INTRODUCTION  5 

kind  that  no  method  of  fighting  them  can  ever  be  completely 
successful.  The  only  thing  is  to  circumvent  them  temporarily, 
keeping  up  a  constant  battle  to  prevent  them  getting  the 
upper  hand. 

When  a  number  of  plants  of  either  the  same  or  dissimilar 
species  are  grown  in  association  the  individuals  of  the  com- 
munity act  and  react  on  one  another  and  determine  the  ulti- 
mate nature  of  the  plant  association.  The  interaction  between 
the  species  is  very  much  affected  by  other  factors  such  as 
moisture,  sunlight,  season,  and  interference  by  man,  and  under 
the  specialised  conditions  of  cultivation  the  interplay  tends  to 
become  obscured  to  a  great  extent.  When  a  large  number 
of  plants  are  growing  in  close  association  keen  competition 
exists  between  them,  and  the  weaker  plants  are  apt  to 
be  smothered  out,  while  the  stronger  continue  to  struggle 
on  together.  This  competition  takes  place  both  below  and 
above  ground.  The  supply  of  moisture  and  available  plant 
food  is  not  inexhaustible,  and  if  a  large  number  of  roots  are 
drawing  from  the  same  area  at  the  same  time  semi-starvation 
threatens  the  plants.  Above  ground  there  is  usually  an  ade- 
quate supply  of  air  and  sunshine,  but  the  vegetation  is  not 
always  in  a  position  to  take  full  advantage  of  it.  If  the  plants 
are  closely  crowded  together  the  leaves  overlap  and  shade  one 
another,  so  that  a  large  proportion  of  them  cannot  be  reached  by 
the  sunlight,  and  in  this  way  the  assimilation  of  carbon-dioxide 
is  hindered  and  the  nutrition  of  the  plants  suffers  accordingly. 
Respiration  is  probably  influenced  less  adversely  under  these 
circumstances  as  the  diffusion  of  the  air  carries  an  abundant 
supply  of  oxygen  even  to  the  shaded  leaves,  and  light  is  not 
essential  to  breathing.  The  harmful  effect  of  overcrowding  is 
constantly  to  be  seen  in  gardens.  If  a  number  of  young 
seedlings  are  allowed  to  grow  on  too  long  in  a  crowded  seed- 
box  they  become  "drawn  up  and  delicate,  and  if  left  undis- 
turbed die  without  making  any  satisfactory  growth.  Even  if 
they  are  planted  out  they  never  make  the  same  robust  and 
healthy  growth  as  do  similar  seedlings  transplanted  before 
the  little  plants  have  time  to  injure  one  another. 

If  the  roots  of  the  associated  plants  feed  at  different  depths 
in  the  soil,  as  for  instance  in  the  case  of  wheat  and  poppy,  the 
underground  competition  is  far  less  severe,  but  the  aerial 
competition  is  so  strong  that  the  plants  may  suffer  as  much  as 
though  all  the  roots  were  at  the  same  level.  Water  culture 
experiments,  in  which  each  barley  plant  had  its  own  individual 


6  WEEDS  OF  FARM  LAND 

food  supply,  have  shown  how  actively  aerial  competition  comes 
into  play  quite  independently  of  the  root  competition.1  When 
the  plants  were  grown  at  some  distance  from  one  another  so 
that  no  shading  occurred  growth  was  strong  and  even,  a  large 
amount  of  dry  matter  being  produced.  When  a  number  of 
plants  were  closely  crowded  together  they  were  far  less  healthy, 
and  the  amount  of  dry  matter  formed  by  individual  plants  de- 
creased as  the  amount  of  shading  by  neighbouring  leaves  in- 
creased. The  crowded  plants  were  unable  to  carry  on  adequate 
carbon  assimilation  owing  to  deficiency  of  light  caused  by  the 
overlapping  of  leaves.  As  this  decrease  of  growth  occurred  even 
when  there  was  no  lack  of  food  for  the  individual  plants  it  is 
obvious  that  aerial  competition  must  play  a  still  more  import- 
ant part  in  the  field  where  the  plants  are  competing  for  food 
as  well  as  light.  Many  of  the  methods  and  processes  of 
cultivation  are  directed  towards  the  elimination  of  this  com- 
petition of  weeds  with  crops,  the  same  end  being  attained  by 
various  systems  of  farming. 

Under  ordinary  farm  management  the  various  crops  are 
grown  in  rotation,  one  of  the  simplest  being  the  four-course 
rotation,  barley,  seeds,  wheat,  roots.  The  seeds  are  sown 
down  with  barley  in  spring,  and  if  germination  is  good  the 
heavy  growth  of  the  barley  tends  to  keep  down  weeds,  while 
the  clover  manages  to  mark  time  until  the  barley  is  cleared  oft 
in  the  autumn.  The  habit  of  growth  of  the  clover  prevents 
the  ordinary  weeds  from  making  much  headway,  although  a 
number  of  special  weeds  are  often  introduced  by  this  crop. 
Consequently,  when  the  clover  makes  way  for  the  wheat  the 
land  is  not  weed-ridden  if  the  barley  and  clover  have  been 
good.  The  weeds  have  not  had  much  chance  to  develop  and 
to  seed,  and  those  introduced  by  the  clover  are  not  usually 
permanent.  With  the  autumn-sown  wheat  the  weeds  get 
their  chance.  The  seeds  buried  in  the  soil  rush  into  growth, 
and  the  wheat  crop  is  full  of  a  great  variety  of  weeds  unless 
some  proportion  of  them  is  removed  by  spring  cultivation. 
Even  so  the  wheat  stubble  is  a  veritable  flower  garden,  and 
is  full  of  many  varieties  of  weeds  ripening  their  seeds  in 
readiness  for  the  future.  After  such  a  fouling  crop  as  wheat, 
therefore,  roots  follow  on  well,  as  they  offer  a  good  oppor- 
tunity to  clean  the  land  and  to  improve  the  condition  of  the 
soil  by  cultivation,  ready  for  the  next  cycle  of  crops. 

1Brenchley,  W.  E.  (1919),  "Some  Factors  in  Competition,"  Joum. 
Applied  Biology,  VI,  Nos.  2  and  3,  pp.  142-170. 


INTRODUCTION  7 

Rather  curious  things  happen  if  no  rotation  is  followed, 
but  the  same  crop  is  grown  on  the  land  year  after  year  without 
intermission.  Several  fields  at  Rothamsted  have  been  under 
continuous  cropping  for  many  years,  and  the  differences  in  the 
weed  floras  are  of  the  most  striking  nature.  The  fields  are 
divided  into  plots  which  are  manured  in  various  ways,  and  the 
differences  in  manuring  and  the  time  of  sowing  the  crops  have 
a  considerable  influence  upon  the  number  and  variety  of  the 
weeds.  Broadbalk  field  at  Rothamsted  has  carried  autumn- 
sown  wheat  regularly  since  1843,  so  that  as  soon  as  one  crop 
is  harvested  it  is  necessary  to  plough  up  the  stubble  in  pre- 
paration for  sowing  the  next  year's  crop.  Consequently,  there 
is  never  any  opportunity  of  thoroughly  cleaning  the  ground 
by  winter  fallow,  and  as  a  wheat  crop  does  not  admit  of  much 
cultivation  in  the  ordinary  way,  a  very  special  state  of  affairs 
has  risen  with  regard  to  the  weeds.  Black  bent  (Alopecurus 
agrestis]  (which  occurs  to  some  extent  on  many  fields  in  the 
district  but  not  plentifully  enough  to  cause  any  trouble)  grows 
up  with  the  corn  and  ripens  its  seeds  at  the  same  time  as  the 
wheat,  so  that  harvesting  operations  tend  to  scatter  the  seed 
freely  on  the  ground.  (Fig.  I.)  These  seeds  germinate  at 
once,  in  the  autumn,  and  the  plants  develop  alongside  the 
wheat,  from  which  in  their  young  stages  they  are  not  easily  dis- 
tinguished by  casual  observation.  Under  rotation  farming  the 
weed  does  not  get  a  serious  hold,  as  it  is  soon  cleared  out  by 
the  cultivation  of  barley  and  roots.  On  Broadbalk,  however, 
no  opportunity  arises  of  ridding  the  ground  of  the  young 
black  bent  plants  before  the  wheat  has  to  be  sown,  and  with 
the  lapse  of  years  the  pest  has  spread  to  such  a  great  extent 
that  it  entails  very  great  expense  for  hand  labour  to  free  the 
crop  in  order  to -prevent  the  experiments  being  spoiled.  It  is 
necessary  to  hoe  out  the  rows  in  early  summer,  and  in  bad 
seasons  to  hand-pull  the  plants  in  order  to  remove  as  many 
as  possible  before  they  have  a  chance  to  seed.  It  is  not  at 
all  uncommon  for  heaps  of  black  bent  3  or  4  feet  high  to  be 
removed  from  each  plot  of  -J  acre.  The  strong  measures 
necessary  for  fighting  this  weed  help  to  keep  the  others  in 
check,  so  that  no  other  species  presents  such  a  difficult 
problem. 

The  adjoining  H«*s  field  has  carried  barley  every  year  since 
1852,  but  as  the  barley  is  spring  s^wn  the  weed  problem  is 
far  less  acute.  The  time  that  elapses  between  harvesting  in 
August  *r  September  and  sowing  in  the  spring  is  sufficiently 


WEEDS  OF  FARM  LAND 


FIG.  i.— BLACK  BENT  (Alopecurns  a^restis). 


INTRODUCTION  9 

long  to  allow  the  land  to  be  well  worked  over,  so  that  no  single 
weed  has  the  opportunity  of  obtaining  such  a  hold  as  black 
bent  has  on  Broad  balk.  At  the  present  time,  however,  the 
perennial  corn  sowthistle  (Sonchus  arvensis]  is  causing  much 
trouble  in  Hoos  field,  as  it  spreads  by  underground  stems,  and 
the  broken  pieces  left  after  cultivation  shoot  up  again  with  the 
barley. 

In  contrast  to  Broadbalk  and  Hoos,  Barn  field  is  devoted 
exclusively  to  root  crops.  Sugar  beet  used  to  be  grown,  but 
of  late  years  mangolds  have  been  taken  instead.  The  field  is 
remarkable  for  the  poverty  of  its  weed  flora.  At  no  time  in 
the  year  do  a  large  number  of  weeds  occur,  and  the  variety 
of  species  is  small.  Some  chickweed  and  groundsel,  a  few 
creeping  thistles  and  greater  plantain,  represent  the  major  part 
of  the  weed  population  at  any  period  of  the  year,  and  even 
after  the  winter,  just  previous  to  ploughing,  the  same  thing  is 
seen.  The  continuous  growth  of  roots  for  so  many  years, 
with  the  attendant  cultivating  and  hoeing,  has  cleared  the 
land  of  most  of  the  weed  seeds  which  may  have  been 
originally  buried  in  it,  and  has  also  prevented  weed  colonists 
from  establishing  themselves  and  shedding  their  seeds. 

Many  of  the  points  touched  on  in  this  introduction  will  be 
dealt  with  more  fully  in  later  chapters,  but  enough  has  been 
said  to  indicate  the  vital  importance  of  a  right  understanding 
of  the  weed  problem  if  it  is  to  be  approached  in  such  a  way  as 
to  render  profitable  assistance  to  the  farmer.  With  the  im- 
provements in  agricultural  machinery  and  the  greater  applica- 
tion of  chemical  knowledge  to  agriculture  in  the  direction  of 
manures  and  sprays,  it  is  conceivable  that  it  may  be  possible 
at  no  distant  date  to  hold  the  weeds  far  more  under  control 
than  has  ever  been  the  case  in  the  past. 


CHAPTER  II. 

DISTRIBUTION  OF  WEEDS. 

THE  flora  of  any  country  or  district  usually  comprises  many 
hundreds  or  thousands  of  species,  but  of  these  compara- 
tively few  are  conspicuous  as  weeds  of  cultivation.  This  is  to 
a  very  great  extent  determined  by  the  fact  that  cultural  con- 
ditions are  mimical  to  the  growth  of  many  wild  plants  which 
resent  interference  with  their  normal  conditions  of  life.  The 
extent  ofthe  weed  flora  is  further  circumscribed  by  the  fact  that 
many  plants,  though  able  to  withstand  the  conditions  peculiar 
to  cultivation,  are  so  ill  adapted  to  arrange  for  their  own  repro- 
duction under  the  specialised  circumstances  that  they  fail  to 
maintain  their  position  and  are  therefore  practically  unknown 
as  weeds.  The  most  familiar  and  widespread  weeds  are  those 
plants  which  are  the  best  adapted  to  meet  the  difficulties  which 
arise  from  the  carrying  on  of  the  various  operations  of 
cultivation. 

The  methods  ot  weed  distribution  are  many  and  various, 
but  may  be  broadly  divided  into  two  classes,  though  the  divid- 
ing line  cannot  always  be  sharply  maintained  :— 

(1)  Methods  which  are  independent  of  any  special  adapta- 
tions for  distribution  developed  by  the  plants. 

(2)  Methods  which  are  dependent  upon  special  adaptations 
for  distribution  developed  by  the  plants. 

i.  METHODS  WHICH  ARE  INDEPENDENT  OF  ANY  SPECIAL 
ADAPTATIONS  FOR  DISTRIBUTION  DEVELOPED  BY  THE 
PLANTS. 

(a)  Various  Means  of  Transport,  as  in  Cargoes,  Ballast,  etc., 
including  the  Transport  of  Impure  Seed. — Distribution  by  means 
of  transport  must  be  held  accountable  for  the  spread  into  vari- 
ous parts  of  the  world  of  many  of  the  worst  weeds  of  culti- 
vation. With  the  increase  in  trading  facilities  and  the  opening 
up  of  fresh  shipping  routes  there  has  come  a  notable  change 


DISTRIBUTION  OF  WEEDS  n 

in  the  weed  floras  of  many  districts,  and  the  difficulties  of  agri- 
culturists have  thereby  in  many  cases  been  greatly  augmented. 
As  is  shown  below,  weed  seeds  are  transported  from  one 
country  to  another  in  various  ways,  and  it  frequently  happens 
that  a  weed  that  is  of  little  or  no  account  in  its  country  of 
origin  finds  the  conditions  of  a  foreign  land  so  congenial  that 
it  spreads  and  becomes  a  veritable  pest,  often  needing  legis- 
lation for  its  suppression.  Sometimes,  too,  with  change  in 
methods  of  cultivation,  an  alien  weed  flora  may  crowd  out  the 
native  weeds  more  or  less  completely.  In  the  settled  por- 
tions of  New  Zealand  and  Australia,1  where  clearings  have 
been  made  and  introduced  crops  like  wheat  are  grown,  the 
alien  weeds  are  most  conspicuous  and  dominate  the  situation. 
Apparently  the  native  plants  are  adversely  affected  by  the  in- 
terference due  to  the  new  methods  of  cultivation,  and  are  un- 
able to  withstand  the  comp  tition  of  the  foreign  plants  ot 
which  the  seeds  are  introduced  with  the  crop  seeds,  and  as  a 
result  the  intruders  have  been  able  to  gain  a  firm  foothold. 
A  considerable  intrusion  of  Northern  plants  into  the  New 
Zealand  flora  has  occurred.  When  a  party  of  the  British 
Association  visited  the  country  in  1914  much  watercress  was 
noted  in  one  place,  and  in  other  localities  Geranium  molle  and 
G.  robertianum  (the  former  a  typical  arable  weed)  were 
completely  naturalised. 

The  extent  to  which  weed  seeds  can  be  carried  from  one 
country  to  another  in  cargoes  of  grain  and  other  crop  seeds 
has  been  well  shown  by  Stapledon,2  who  has  proved  that  it  is 
possible  to  trace  the  country  from  which  samples  of  commercial 
oats  have  originated  by  means  of  the  quantity  and  varieties  of 
weed  seeds  that  are  present  For  instance,  oats  from  Russia 
usually  contain  an  abundance  of  corn  cockle,  and  wild  vetches 
and  field  bindweed  are  also  often  plentiful.  Turkey  seed 
is  characterised  by  the  presence  of  a  considerable  amount  of 
Rapistrum  rugosum,  an  unidentified  Medicago,  and  a  fair 
quantity  of  darnel  and  sweet  clovers ;  Canadian  origin  is 
shown  by  excess  of  ball  mustard  (Neslia  paniculatd]  and  by 
blue  bur  (Lappula  echinatd)  and  prairie  sunflower,  while  in 
British  seed  black  bindweed  (Polygonum  convolvulus}  and 
charlock  (Brassica  spp.~]  are  often  the  only  weed  seeds, 

1  Rendle,  A.  B.  -(1915),  "  The  British  Association  in  Australia,"  Jour.  Bot., 
LIII,  No.  625,  pp.  23-34. 

J  Stapledon,  R.  G.  (1916),  "  Identification  of  the  Country  of  Origin  of  Com- 
mercial Oats,"  jour.  Bd.  Agric.,  XXIII,  No.  2,  pp.  105-116. 


12  WEEDS  OF  FARM  LAND 

though  a  wild  oat  (Avena  strigosa)  is  sometimes  met  with. 
An  examination  of  the  Canadian  weed  flora  is  illuminat- 
ing. Out  of  seventy  of  the  worst  agricultural  weeds  that  are 
fully  described  and  figured  by  the  Department  of  Agriculture l 
forty-seven  are  characterised  as  being  introduced  from  Europe, 
one  from  Asia,  and  one  from  Tropical  America,  only  twenty- 
one  being  indigenous. 

Weed  seeds  may  be  carried  from  country  to  country,  not 
only  among  crop  seeds,  but  also  in  ballast  or  with  forage  of 
various  kinds.  An  analysis  of  the  flora  of  an  old  ballast  heap 
at  Linnton,  Oregon,  on  the  Pacific  coast,  showed  2  thirty-two 
species  indigenous  on  the  Pacific  coast,  eighty-eight  species 
introduced  to  the  district  but  occurring  elsewhere  in  Oregon, 
and  ninety  three  species  collected  only  on  the  Linnton  ballast 
area  and  not  found  in  other  parts  of  the  state. 

Probably  50  per  cent,  of  the  list  of  species  cited  by  Nelson 
have  been  collected  for  the  first  time  on  the  Pacific  coast,  or 
at  least  within  the  limits  of  the  State  of  Oregon.  If  infor- 
mation were  available  it  would  doubtless  be  found  that  a 
similar  state  of  affairs  exists  in  other  places  where  ballast  is 
dumped.  In  our  own  country  much  distribution  is  effected 
by  the  carriage  of  waste  dust  and  rubbish  by  railway  to  dumps 
in  various  parts  of  the  country.  It  is  quite  usual  to  find  such 
dumps  colonised  by  plants  which  are  not  native  to  the  locality, 
but  whose  origin  can  be  traced  to  the  district  from  which  the 
waste  material  was  brought.  It  is  probable  that  a  good  deal 
of  weed  distribution  is  effected  in  this  manner,  for  if  conditions 
are  suitable  an  introduced  plant  will  quickly  establish  itself 
and  may  become  a  troublesome  pest. 

(£)  Carriage  in  Manure. — That  weed  seeds  may  be  spread 
by  manure  from  an  infested  district  is  a  danger  whose  reality 
is  too  little  recognised.  If  manure  is  stacked  in  a  field 
for  some  time  prior  to  use  it  rapidly  becomes  covered 
with  weeds,  among  which  fat  hen  (Chenopodium  albuni]  (Fig.  2) 
and  orache  (A triplex  patuld]  (Fig.  3)  are  often  conspicuous. 
The  seeds  of  these  plants  and  many  others  are  transported  in 
the  manure,  which  thus  becomes  a  ready  source  of  infestation. 
Only  too  often  the  litter  used  for  bedding  cattle  contains  much 
rubbish  that  is  full  of  weed  seeds,  and  unless  excessive  heat- 
ing takes  place  many  of  these  seeds  retain  their  power  of 

1  Clark,  G.  H.,  and  Fletcher,  J.  (1909),  "  Farm  Weeds  of  Canada  ". 
2Nelson,  J.  C.  (1917),  "The  Introduction  of  Foreign  Weeds  in  Ballast,  as 
illustrated  by  Ballast  Plants  at  Linnton,  Oregon,"  Torreya,  XVII,  pp.  151-160. 


DISTRIBUTION  OF  WEEDS 


FIG.  2.— FAT  HEN  (Chenopodium  album). 


14  WEEDS  OF  FARM  LAND 

germination  for  a  long  period  and  are  ready  to  start  into 
growth  when  they  are  dug  into  the  soil  with  the  manure. 
Little  is  known  about  the  amount  of  heating  that  weed  seeds 
can  withstand  when  buried  in  manure,  but  it  is  certain  that  under 
the  ordinary  conditions  of  making  and  storing  dung  large 
quantities  of  seeds  escape  destruction.  If  it  can  be  avoided, 


FIG.  3. — ORACHE  (Atriplex  patula). 

therefore,  it  is  best  riot  to  spread  manure  as  soon  as  it  is 
received  from  any  district  known  to  be  badly  infested  with 
weeds.  If  the  manure  can  be  properly  stored  for  some  time, 
there  is  a  possibility  that  many  of  the  seeds  will  rot  and  that 
many  others  will  take  advantage  of  the  genial  warmth  to  start 
germinating,  only  to  perish  from  the  adverse  conditions  for 
plant  life  that  exist  within  the  heap. 


DISTRIBUTION  OF  WEEDS  15 

The.  danger  of  weed  transport  in  manure  is  probably  less 
nowadays  than  it  used  to  be,  as  with  the  improvement  in 
threshing  tackle  a  much  cleaner  separation  of  grain,  straw  and 
rubbish  is  effected,  and  the  practice  of  burning  the  rubbish 
(containing  most  of  the  weed  seeds)  is  becoming  more  widely 
spread.  Also  there  is  comparatively  little  transport  of  manure 
from  one  country  district  to  another,  but  where  stable  manure 
is  brought  from  towns  much  care  should  be  exercised,  as 
the  litter  and  feeding  stuffs  are  more  likely  to  be  contamin- 
ated with  weed  seeds  than  in  the  case  of  manure  produced  on 
farms. 

(c)  Distribution  by  Means  of  Farm  Implements. — With  the 
increase  in  the  use  of  farm  machinery  of  late  years  the  danger 
of  weed  infestation  from  this  source  has  become  more  acute. 
Almost  every  implement  that  is  used  in  farm  operations  may 
serve  as  a  carrier  of  seeds  or  growing  parts  of  weeds,  but  as 
hand  implements  and  the  smaller  horse  machines  are  usually 
the  property  of  the  farm,  weed  distribution  by  this  means  is 
localised.     With  the  advent  of  peripatetic  tractors,  threshing 
machines,  reapers  and  binders,  etc.,  the  area  of  distribution 
was  at  once  widened,  and  now  care  is  necessary  to  prevent 
trouble  arising.      Farm  implements  spread  weeds  in  various 
ways,  the  most  obvious  being  by  means  of  the  clods  of  earth 
that  are  carried  about  on  the  wheels  and  on  the  horses'  hoofs. 
The  soil  is  full  of  weed  seeds  and  in  many  cases  broken  pieces 
of  weed  are  also  present  which  are  capable  of  striking  root 
elsewhere.     If  machinery  passes  from  farm  to  farm  over  a  wide 
area,     from    badly-tilled    farms   to   well-cultivated    ones,   the 
efforts  of  careful  farmers  to  reduce  their  weed  population  may 
be  greatly  hindered  if  they  do  not  take  care  that  the  incoming 
machines  are  well  cleaned  before  they  are  allowed  to  pass  on 
to  the  land.     Threshing  machines  introduce  another  problem, 
as  weed  seeds  collect  within  them,  only  to   pass   out  when 
further  threshing  is  carried   out.      Such   weeds  as   wild   oats 
(Avena  fatua)  are  particularly  troublesome  in  this  way,  as  not 
only  are  they  bad  weeds  on  the  land,  but  the  hairy  fruits  with 
their  bent  and  twisted  awns  collect  in  balls  and  rapidly  choke 
up   the   machine  (Fig.    4).     Here  again    scrupulous  care    in 
cleaning  before  use  is  necessary  if  weed  distribution  is  to  be 
avoided. 

(d)  Carriage  by  Moisture  or  in  Mud. — Though  to  some  ex- 
tent mud  carriage  is  dealt  with  under  the  preceding  heading 
other  aspects  must  be  considered  here.     Traffic  of  every  kind 


i6 


WEEDS  OF  FARM  LAND 


helps  to  distribute  weeds,  as  mud  containing  the  seeds  is 
carried  about  on  the  feet  of  stock,  cartwheels,  boots  of  human 
beings,  walking  sticks,  and  in  various  other  ways.  This  is 
often  well  shown  along  cart  tracks  or  round  gateways  through 
which  much  traffic  passes,  as  an  assemblage  of  weeds  character- 
istic of  different  situations  may  often  be  found  there.  For 
instance,  the  trampled  mud  round  a  single  gate  between  a 
public  road  and  a  ploughed  field  on  chalky 
Boulder  clay  was  colonised  by 1 : — 

(1)  Arable  PFm&  (from  field).— Slender 
foxtail,  scarlet  pimpernel,  charlock,  fat  hen, 
dwarf  spurge,   knotgrass,   groundsel,  field 
speedwell. 

(2)  Grass-land  Plants  (from  grass  by 
roadside).  —  Ryegrass,     cat's-tail,    greater 
plantain,  broad-leaved  dock,  couchgrass, 

(3)  Weeds  found  in  both  Situations. — 
Silverweed  and  creeping  thistle. 

Traffic  over  such  an  area  in  muddy 
weather  would  be  a  constant  means  of 
weed  distribution.  It  can  easily  be  under- 
stood that  mud  containing  weed  seeds  may 
be  transported  for  very  long  distances 
when  it  is  carried  on  the  feet  of  animals 
or  on  the  boots  of  men  travelling  by  train 
or  motor.  On  the  whole  it  is  the  arable 
weeds  that  are  chiefly  distributed  in  this 
way,  as  roadside  weeds  usually  have  more 
specialised  arrangements.  The  carriage 
of  mud  on  cartwheels  is  often  responsible 
for  the  temporary  appearance  of  arable 
weeds  in  grass  fields,  as  such  plants  as 
shepherd's  purse,  swinecress,  chamomile,  mayweed,  spurry,  and 
poppies  will  all  spring  up  along  wheel  tracks  across  grass, 
though  they  rarely  persist  for  more  than  one  season  unless 
the  grass  is  obliterated  and  bare  soil  conditions  prevail. 

The  spread  of  weeds  by  "  damp  carriage  "  is  rarely  recog- 
nised, but  many  seeds  will  adhere  to  damp  boots  or  clothing 
where  there  is  an  entire  absence  of  mud.  Groundsel,  ragwort, 
hawkbit,  daisy,  buttercup,  dandelion,  mouse-ear  chickweed,  and 
the  seeds  of  various  grasses  may  all  be  collected  and  transferred 

1  Woodruffe  Peacock,  E.  A.  (1918),  "  The  Means  of  Plant  Dispersal :  Mois- 
ture and  Mud  Carriage,"  Selbome  Magazine,  XXIX,  No.  338,  pp.  20-22. 


FIG.  4. — SPIKELET  OF 
FRUITS  OF  WILD 
OAT  (Avena  fatua), 
showing  the  hairs 
and  the  twisted 
awns. 


DISTRIBUTION  OF  WEEDS  17 

from  grassy  areas,  while  forget-me-not,  field  speedwell,  fool's 
parsley,  and  persicaria  are  among  the  arable  weeds  that  have 
been  observed  to  be  distributed  in  this  way.  Many  weed 
seeds  are  rather  sticky  when  damp  and  tend  to  adhere  closely 
to  anything  they  touch,  so  that  they  are  easily  carried  about 
from  one  place  to  another. 

(e)  Distribution  by  High  Winds  and  Storm  Columns. — Very 
little  seems  to  be  known  on  this  subject,  but  one  observer, 
WoodrufTe  Peacock,  has  specially  studied  the  point,1  and  his 
results  suggest  that  this  is  a  far  more  important  means  of  dis- 
tribution than  is  generally  recognised.  Ordinary  wind  drift 
will  carry  seeds  some  distance,  but  this  is  very  local.  Wood- 
rufTe Peacock  cites  a  case  of  such  distribution  of  charlock 
recorded  in  Thompson's  "  History  of  Boston,"  and  if  this  could 
be  more  universally  established  it  might  throw  some  light 
on  the  continual  appearance  of  charlock  when  grass  land  is 
ploughed  up,  or  old  arable  land  free  from  the  weed  is  ploughed 
more  deeply.  Seeds  of  mithridate  mustard  (Thlaspi  arvense) 
in  Cadney  (Lines)  were  carried  by  a  single  spring  gale  over 
half  a  mile  of  arable  peat.  Whirlwinds  or  small  local  storm 
columns  will  lift  and  shift  seeds  for  distances  up  to  1 50  yards, 
but  storm  columns  can  carry  materials  for  miles.  Distribution 
over  an  area  of  at  least  twenty-five  miles  has  been  observed  in 
Lincolnshire.  In  1897  a  storm  column  brought  to  Cadney 
a  variety  of  plants  for  which  the  nearest  habitat  was  twenty 
to  twenty-five  miles  away.  Among  these  were  wild  onion 
(Allium  vineale)  and  couch  grass,  while  heavy  plants  of  tufted 
vetch  (Vicia  cracca),  including  the  root,  were  also  carried.  A 
list  of  the  plants  that  WoodrufTe  Peacock  has  personally  noted 
to  be  carried  by  storm  columns  in  this  country  may*be  inter- 
esting, as  so  little  information  on  the  point  is  available : — 

Many  grasses. 

Achillea  millefolium  (yarrow).     Cut  fragments. 

Allium  vineale  (wild  onion).     Rooted  plants. 

Anthriscus  sylvestris  (wild  chervil).      Fragments. 

Capselta  bursa-pastoris  (shepherd's  purse).      Rooted  plants. 

Cerastium  vulgatum  (mouse-ear  chickweed).     Rooted  plants. 

Hippocrepis  comosa  (horse-shoe  vetch).     Rooted  plants. 

Leontodon  autumnalis  (autumnal  hawkbit).     Cut  fragments. 

Lotus  corniculatus  (bird's  foot  trefoil).     Rooted  plants. 

1  WoodrufTe  Peacock,  E.  A.  (1917),  "  The  Means  of  Plant  Dispersal," 
Selborne  Magazine,  XXVIII,  pp.  40-44. 

2 


1 8  WEEDS  OF  FARM  LAND 

Ononis  repens  (restharrow).     Broken  pieces. 

Rhinanthus   crista-galli   (yellow    rattle).     Cut  fragments   and 

rooted  plants. 

Rumex  acetosella  (sheep's  sorrel).     Cut  fragments. 
Stellaria  media  (chickweed).     Rooted  plants. 
Vicia  cracca  (tufted  vetch).     Fragments. 

Further  observation  on  this  means  of  dispersal  are  very 
desirable.  Many  weeds  that  are  obviously  distributed  by  means 
of  seeds  have  apparently  no  special  adaptation  for  dispersal, 
and  yet  there  is  no  doubt  that  distribution  does  occur.  It  is 
quite  possible  that  all  the  agencies  at  work  are  not  fully 
known,  and  that  wind  carriage  during  gales  and  storm 
columns  is  of  far  more  importance  than  is  at  present  believed. 

2.  METHODS  WHICH  ARE  DEPENDENT  UPON  SPECIAL 
ADAPTATIONS  FOR  DISTRIBUTION  DEVELOPED  BY  THE 
PLANTS. 

Weeds  having  special  adaptations  that  assist  in  their 
distribution  may  be  broadly  divided  into  two  classes  according 
as  they  are  spread  by  means  of 

A.  fruits  and  seeds  (sexual  reproduction). 

B.  vegetative  parts  (vegetative  reproduction). 

The  line  of  division  is  not  always  sharply  marked,  as  in  some 
weeds  both  types  of  reproduction  are  well  developed,  but  as  a 
general  rule  only  one  method  is  of  real  importance  to  a  par- 
ticular plant.  Those  in  which  both  methods  are  conspicuous 
comprise  some  of  the  worst  of  our  agricultural  weeds,  as 
methods  of  eradication  that  are  directed  against  the  formation 
of  seed  are  not  always  effective  against  the  spread  of  vegeta- 
tive parts  and  vice  versa.  This  double-barrelled  reproduction 
is  specially  noteworthy  in  thistles,  wild  onion,  corn  sowthistle, 
coltsfoot,  and  creeping  buttercup,  though  it  occurs  to  some 
extent  in  various  other  weeds.  In  the  following  classification 
the  same  weed  may  appear  twice  if  the  two  methods  of  dis- 
tribution are  sufficiently  well  marked  to  warrant  it. 

A.  Distribution  by  Fruits  and  Seeds  (Sexual  Reproduction). 

(a)  Seeds  Produced  in  Large  Quantities. — Many  weeds 
that  do  not  have  special  adaptations  for  seed  distribution  are 
safeguarded  by  the  production  of  large  quantities  of  seeds,  so 


DISTRIBUTION  OF  WEEDS  19 

many  being  formed  that  even  if  a  very  large  percentage  is 
lost  or  destroyed  the  surviving  minority  will  be  amply  suffici- 
ent to  provide  an  abundance  of  descendants.  This  method  is 
very  common  and  effective  among  arable  weeds,  especially 
with  those  which  grow  close  to  the  ground.  The  various  pro- 
cesses of  cultivation  are  all  inimical  to  the  survival  of  weeds  ; 
when  the  seeds  germinate  the  seedlings  are  liable  to  be  ruth- 
lessly cut  down  at  various  stages  of  growth.  Under  these 
circumstances  the  presence  of  large  quantities  of  seeds  in  the 


FIG.  5. — KNOTGRASS  (Polygonum  aviculare}. 

soil  is  most  favourable  for  the  weeds  as  the  seeds  do  not  all 
germinate  at  once,  so  that  if  and  when  the  first  batch  of  seed- 
lings is  destroyed,  a  fresh  batch  which  may  have  more  chance 
of  reaching  maturity  springs  up  at  short  notice.  This  may 
be  continued  time  after  time,  as  seeds  from  one  crop  of  weeds 
usually  vary  greatly  in  the  time  that  elapses  before  germina- 
tion, the  period  sometimes  ranging  from  a  few  days  to  several 
years.  Scarlet  pimpernel,  knotgrass  (Fig.  5),  mouse-ear 
chickweed,  spurry,  chickweed,  and  speedwells  of  various 
species  are  all  low  growing  arable  weeds  which  form  such  an 
abundance  of  seed  that  when  once  they  are  established  it  is 


20  WEEDS  OF  FARM  LAND 

difficult  to  get  rid  of  them.  They  spread  over  the  surface  of 
the  ground  with  their  long  trailing  branches,  form  flowers  and 
fruits  in  rapid  succession  along  the  stems,  and  drop  their  seeds, 
which  are  usually  several  in  a  fruit,  directly  into  the  soil  when 
they  are  ripe. 

Charlock  (Brassica  spp.)  produces  an  abundance  of  heavy 
seeds  which  to  all  appearance  have  no  ready  means  of  dis- 
tribution other  than  that  of  falling  into  the  soil  in  the  neigh- 
bourhood of  the  mother  plant.  The  true  method  of  charlock 
distribution,  however,  is  still  a  mystery,  as  it  has  a  habit  of 
turning  up  in  profusion  in  all  sorts  of  places  at  a  distance 
from  the  nearest  source  of  the  seed. 

Dodder  (Cuscuta  spp.}  is  little  other  than  a  seedbox,  as  its 
clusters  of  small  flowers,  ranged  at  frequent  intervals  along  the 
twining  stems,  give  rise  to  multitudes  of  seeds  which  either 
fall  into  the  soil  in  the  immediate  vicinity  or  are  carried  away 
when  the  crop  is  cut,  only  to  start  a  fresh  infestation  of  the 
parasite  elsewhere. 

A  certain  number  of  taller  and  more  upright  weeds  also 
form  quantities  of  seeds,  but  these  are  usually  so  small  and 
light  that  they  are  easily  carried  about  by  the  wind ;  conse- 
quently their  range  of  distribution  is  less  limited,  and  the 
danger  of  loss  when  they  are  carried  away  is  compensated  for  by 
their  abundance.  Shepherd's  purse,  toadrush  (Juncus  bufonius}, 
broomrape  (Orobanche  spp.},  and  poppies  are  good  examples, 
and  in  some  cases,  as  poppy,  the  seed,  capsules  have  adapta- 
tions which  prevent  the  escape  of  the  seed  in  unsuitable 
weather  when  there  is  danger  of  it  becoming  damp  and  clogged. 

(b)  Seeds  Shot  Out. — A  limited  number  of  plants  take  a  very 
active  share  in  their  own  distribution  by  shooting  the  ripe 
seeds  out  to  various  distances.  Crane's-bill  (Geranium  spp.}  and 
stork's-bill  (Erodium  spp.\  which  are  often  present  in  temporary 
pastures,  have  a  fruit  consisting  of  five  pieces  or  carpels  joined 
to  a  central  column,  one  seed  being  present  in  each  carpel  at 
the  base.  When  the  seeds  are  ripe,  some  amount  of  de- 
siccation occurs,  the  carpels  break  away  suddenly  at  the  base 
and  roll  up  backwards,  jerking  the  seeds  out  as  they  go. 
The  fruit  of  vetch  (  Vicia  spp.}  (Fig.  6)  is  a  pod  containing  one 
row  of  seeds.  When  ripe  the  pod  splits  up  both  sides  and 
curls  suddenly  into  a  spiral,  shooting  the  seeds  for  some 
considerable  distance,  often  several  feet.  In  the  spurges 
{Euphorbia  spp.)  the  seeds  are  jerked  away  when  ripe  with 
considerable  force. 


DISTRIBUTION  OF  WEEDS 


21 


This  method  of  seed  distribution  is  highly  specialised,  but 
is  less  effective  than  others.  Comparatively  few  seeds  are 
formed,  and  as  the  risk  of  life  is  very  great  it  seldom  happens 
that  weeds  of  this  description  are  very  abundant.  The 
geraniums  are  usually  associated  with  temporary  pastures, 
because  when  once  the  seed  is  sown  there  is  little  cultural 
interference  and  the  weeds  are  able  to  ripen  seeds  in  peace. 
If  the  ley  is  succeeded  by  tillage  crops 
such  as  cereals  or  roots,  the  geraniums 
usually  disappear  rapidly,  as  there  are  not 
enough  seeds  in  the  soil  to  withstand 
the  processes  of  cultivation. 

(c)  Fruits  and  Seeds  Distributed  by 
Wind. — Adaptations  for  this  purpose  are 
exceedingly  common  and  are  usually  in 
the  form  of  wings  or  hairs  arranged  to 
form  a  kind  of  parachute.  The  wings  or 
hairs  may  be  developed  either  on  the  seed 
itself  or  on  the  fruit,  the  latter  being  more 
general.  Many  of  the  seeds  are  liable  to 
be  lost,  but  they  are  produced  in  large 
quantities  and  under  favourable  circum- 
stances can  be  carried  for  many  miles.  It 
is  on  this  account  that  weeds  with  these 
adaptations  are  so  peculiarly  dangerous, 
for  if  they  are  allowed  to  ripen  their  seeds 
it  is  impossible  to  confine  them  within 
bounds,  and  a  single  dirty  farm  may  vitiate 
all  attempts  at  clean  farming  over  a  wide  FlGt 


area. 


6.  —  FRUIT      OF 

N  ARROW-LEAVED 

VETCH  (Vicia  an- 
gustifolia),  showing 
one  pod  split  open 
and  curled  back  with 
the  seeds  shot  out. 


(a)  Winged  Fruits. — The  winged 
part  may  either  be  firmly  attached  to  the 
fruit  or  may  be  easily  detachable.  In 
several  of  the  Umbellifers,  as  for  instance 
hogweed  (Heradeum  sphondyliuni]  (Fig.  7  C),  a  very  broad 
wing  is  developed  by  the  seed  case,  which  encloses  a  single 
flattened  seed.  In  the  docks  and  sorrels  the  floating  organ 
is  formed  by  the  persistent  floral  envelope  or  perianth,  within 
which  is  the  hard  triangular  fruit  (Fig.  7  D). 

(ft)  Winged  Seeds. — In  toadflax  (Linaria  vulgaris]  and 
yellow  rattle  (Rhinanthus  crista-galli)  (Fig.  7  A)  each  seed  is 
provided  with  a  broad  wing,  so  that  it  is  easily  carried  by  the 
wind.  In  some  other  cases,  as  in  spurry  (Fig.  7  B),  a  very 


22  WEEDS  OF  FARM  LAND 

narrow  wing  is  developed,  but  this  is  so  small  in  proportion 


A 


D 

FIG.  7. — WINGED  SEEDS  AND  FRUITS. 

A.  Winged  Seed  of  Yellow  Rattle  (Rhinanthns  crista-galli). 

B.  Winged  Seed  of  Spurry  (Spergula  arvensis). 

C.  Winged  Fruit  of  Hogweed  (Heracleum  Sphondylium}.     Wing  developed  from 

Fruit  Coat. 

D.  Winged  Fruit  of  Broad-leaved  Dock  (Rumex  obtusifolius).     Wing  consists  of 

persistent  Perianth. 

(The  small  sketches  are  natural  size.) 

to  the  size  of  the  seed  that  it  is  doubtful  if  it  is  an  effective 
agent  in  distribution. 


DISTRIBUTION  OF  WEEDS  23 

(7)  Plumed  Fruits. — By  far  the  greatest  number  of  wind- 
carried  weeds  are  provided  with  this  type  of  mechanism,  and 
the  great  majority,  if  not  all,  belong  to  one  order  of  plants, 
the  Compositae.  The  Compositae,  world-wide  in  distribu- 
tion and  outstanding  in  number  of  species  and  in  the 
multitude  of  individuals,  most  probably  owe  much  of  their 
pre-eminence  to  the  fact  that  they  have  developed  a 
thoroughly  efficient  method  of  distributing  their  seeds.  The 
plumed  fruits  vary  in  size,  some  being  quite  tiny  while 
others  are  comparatively  large  and  heavy,  but  all  agree 
in  having  the  calyx,  or  outer  floral  envelope  modified  into  a 
number  of  hairs  called  the  pappus.  These  hairs  radiate 
from  a  common  centre,  sometimes  rising  directly  from  the  top 
of  the  fruit  (as  in  groundsel  and  coltsfoot),  sometimes  being 
raised  above  the  fruit  on  a  slender  beak,  as  in  dandelion  and 
goatsbeard.  There  is  great  variation  in  the  type  of  hairs,  for 
in  some  cases  they  are  short  bristles,  as  in  hardhead  ;  in 
others  they  are  quite  simple  but  long  and  silky,  as  in  groundsel ; 
in  others  they  are  feathered,  as  in  creeping  thistle,  and  yet 
again  the  hairs  may  be  outstanding  and  interlacing  so  as  to 
form  a  kind  of  web,  as  is  well  seen  in  goatsbeard.  Among  the 
common  weeds  that  possess  plumed  fruits  may  be  mentioned 
thistles  (Cirsium  arvense  (Fig.  8  B),  C.  lanceolatum,  Carduus 
nutans,  etc.),  cudweeds  (Filago  germanica  and  Gnaphalium 
uliginosum),  groundsel  (Senecio  vulgaris)  (Fig.  8  E),  sowthistle 
(Sonchus  arvensis  and  .$.  oleraceus],  dandelion  (Taraxacum 
vulgar  e}  (Fig.  8  D),  goatsbeard  (Tragopogon  pratensis)  (Fig. 
8  F),  coltsfoot  (Tussilago  farfara)  (Fig.  8  A),  hawksbeard 
(Crepis  spp.\  mouse-ear  hawk  weed  (Hieracium  pilosella),  hawk- 
bit  (Leontodon  spp.)  (Fig.  8  C).  The  common  hardhead  (Cen- 
taurea  nigra)  has  only  short  scaly  bristles,  sometimes  mixed 
with  a  few  longer  ones,  but  the  greater  knapweed  (C.  scabiosd) 
is  crowned  with  a  pappus  of  stiff  hairs  almost  as  long  as  the 
fruit  itself. 

(8)  Plumed  Seeds. — Comparatively  few  plants  are  pro- 
vided with  plumed  seeds,  the  only  outstanding  instances  among 
British  weeds  being  the  willow-herbs  (Epilobium  spp.}  (Fig.  9). 
The  fruit  is  long  and  narrow  and  when  ripe  splits  into  four 
pieces  which  curl  back  and  liberate  the  numerous  small  seeds, 
each  of  which  bears  a  tuft  of  hairs. 

(d)  Fruits  and  Seeds  Distributed  by  Animals  and  Human 
Beings. — Two  distinct  methods  of  distribution  are  included 
under  this  heading,  in  one  of  which  the  fruits  and  seeds  attagh 


WEEDS  OF  FARM  LAND 


FIG.  8. — PLUMED  FRUITS. 

A.  Coltsfoot  (Tussilago  farfara).  D.   Dandelion  (Taraxacum  vulgar  e). 

B.  Creeping  Thistle  (Cirsium  arvense).  E.  Groundsel  (Scnecio  vulgaris). 

Cr   Hawkbiij(Leontodon  hispidus).  £  F.  Goatsbea'rd  (Tragopogonpratensis). 

(The  small  sketches  are  natural  size.) 


DISTRIBUTION  OF  WEEDS 


25 


themselves  mechanically  to  the  active  distributing  agent,  and 
in  the  other  are  swallowed  with  the  food  and  are  ejected 
uninjured  after  passing  through  the  body  of  the  animal. 

The  fruits  of  agrimony  (Fig.  10  A),  wild  carrot  (Fig. 
10  B),  goosegrass  (Fig.  10  C)  and  corn  buttercup  (Fig.  10  D 
and  Fig.  n)  are  all  provided  with  hooks  of  various  types 
which  catch  on  to  the  wool  or  hair  of  animals  that  pass 


A 


FIG.  9. — PLUMED  SEEDS  OF  WILLOW-HERB  (Epilobium  sp.). 

A.  Fruit  split  open,  showing  Seeds. 

B.  Single  Seed,  natural  size,  showing  Plume. 

C.  Seeds,  enlarged. 

amongst  them,  or  on  to  the  clothing  of  human  beings.  Shep- 
herd's needle  (Fig.  12)  has  less  obvious  hooks,  but  the  fruits 
are  distinctly  rough  and  are  well  able  to  cling.  The  bent 
awn  and  numerous  hairs  of  wild  oat  (Avena  fatud)  aid  in  its 
distribution  by  animals,  and  it  is  possible  that  the  hygroscopic 
character  of  the  awn,  which  twists  and  untwists  according  to 
the  dampness  of  the  air,  may  also  play  a  part  in  the  spread  of 
this  weed, 


26 


WEEDS  OF  FARM  LAND 


A  considerable  amount  of  seed  distribution  is  probably 
carried  out  unconsciously  by  human  beings,  as  seeds  of  many 
kinds  of  wild  plants  have  a  habit  of  working  their  way  into 
pockets  and  folds  of  the  clothes.  The  following  weed  and  grass 


B 


FIG.  10. — HOOKED  FRUITS. 

A.  Agrimony  (Agrintonia  eupatoria). 

B.  Wild  Carrot  (Daucits  carota). 

C.  Goosegrass  (Galium  aparine). 

D.  Corn  Buttercup  (Ranunculus  arvensis). 

seeds  have  all  been  collected  from  human  clothing *  and  give  a 
good  idea  of  the  diversity  of  species  that  may  thus  be  spread. 
Avens  (Geum  urbanum),  buttercup  (Ranunculus  bulbosus  and 
R.  acris\  cocksfoot,  couch  grass,  dandelion  (Taraxacum  vul- 
gare),  dock  (Rumex  sanguineus),  enchanter's  nightshade 

1  I  am  indebted  to  the  Rev.  E.  A.  Woodruffe  Peacock  for  the  loan  of  tubes 
containing  seeds,  etc.,  collected  from  human  clothing.  The  above  list  is  drawn 
up  from  the  identifications  thus  obtained, 


DISTRIBUTION  OF  WEEDS 


27 


(Circcea  lutetiana},   forget-me-not  (Myosotis  arvensis),    foxtail 
(Alopecurus  pratensis),  goosegrass  (Galium  aparine),  hogweed, 


FIG.  ii. — CORN  BUTTERCUP  (Ranunculus  arvcnsis),  showing  Flowers  and 
Clusters  of  Fruits. 

sterile  brome  (Bromus  sterilis),  tall  fescue  (Festuca  elatior\ 
tall  oat  (Arrhenatherum  avenaceum),  wall  barley  (Hordeum 
murinutri),  yellow  oat  (Avena  flavescens),  Yorkshire  fog. 


28 


WEEDS  OF  FARM  LAND 


Experiments  have  shown  that  large  numbers  of  weed  seeds 
retain  their  power  of  germination  and  growth  even  after  they 
have  passed  through  the  digestive  tracts  of  animals  (see  p.  74). 
As  animals  often  traverse  long  distances  in  a  comparatively 
short  time  they  are  able  in  this  way  to  accomplish  a  good  deal 
of  seed  distribution,  and  may  on  occasion  be  responsible  for 
the  introduction  of  a  weed  into  a  fresh  locality. 

(e)  Fruits  and  Seeds 
Distributed  by  Birds. — 
Birds  may  either  carry 
seeds  about  on  their  feet, 
feathers  or  bills,  or  they 
may  eat  them  for  food  and 
void  a  certain  proportion 
uninjured.  Ducks,  water 
hens,  and  other  birds  have 
been  proved  to  carry 
species  of  water  plants 
from  one  piece  of  water 
to  another  by  means  of 
wet  seeds  or  pieces  of  the 
actual  plant  sticking  to 
them.  Creeping  butter- 
cup (Ranunculus  repens] 
often  occurs  on  the  damp 
edges  of  ponds  and  is 
known  to  be  carried  about 
by  ducks  and  water  hens.1 
Enormous  numbers  of 


FIG.  12. — SHEPHERD'S  NEEDLE  (Scandix 
pecteri),  showing  the  Small  Flowers  and 
much  Elongated  Fruits. 


weed  seeds  are  eaten  by 
wild  birds,  and  though  it 
is  usually  assumed  that 
all  such  seeds  are  destroyed  this  is  not  the  case.  Collinge's  2  3 
experiments  have  shown  that  birds  are  in  this  way  responsible 
for  the  distribution  of  many  common  weeds,  including  ribwort 
plantain,  mouse-ear  chickweed,  groundsel,  sheep's  sorrel,  daisy, 
yarrow,  creeping  buttercup,  dandelion,  chickweed,  charlock, 
dock,  knotgrass,  goosegrass,  and  various  others.  From  the 

1  Woodruffe  Peacock,  E.  A.  (1917),  "  Means  of  Plant  Dispersal,"  Selborne 
Magazine,  XXVIII,  pp.  80-83,  97-101,  114-116;  (1918),  XXIX,  pp.  9-12. 

2  Collinge,  W.  E.  (1913),  "  Destruction  and  Dispersal  of  Weed  Seeds  by  Wild 
Birds,"  Jouvn.  Bd.  Agric.,  XX,  pp.  15-26. 

3  Collinge,  W.  E.  (1914),  "  Some  Further  Observations  on  the  Dispersal  of 
Weed  Seeds  by  Wild  Birds,"  Journ.  Econ.  Biology,  IX,  pp.  69-71. 


DISTRIBUTION  OF  WEEDS  29 

results  of  these  experiments  it  is  probable  that  seed-eating  birds 
are  far  more  active  as  distributors  of  weed  seeds  than  is  usually 


FIG.  13. — BINDWEED  (Convolvulus  arvensis). 
A.  Aerial  Shoot.     B.  Underground  Stem. 

imagined.      Evershed  examined  many  pheasant  crops  x  and 

1  Evershed,  A.  F.  C.  H.  (1918),  "  Pheasants  and  Agriculture,"  Journ.  Ag. 
Sci.,  IX,  pp.  63-91. 


WEEDS  OF  FARM  LAND 


DISTRIBUTION  OF  WEEDS 


found  large  numbers  of  weed  seeds  therein.  In  some  cases 
hundreds  or  thousands  of  seeds  of  one  species  were  present  In 
a  single  crop,  and  if  even  a  small  percentage  of  these  passed 
unharmed  through  the 
bird  a  great  deal  of 
weed  distribution 
would  be  effected. 
The  most  abundant 
seeds  were  those  of 
fat  hen,  knotgrass, 
bindweed,  field  pansy, 
persecaria,  chickweed 
and  buttercup,  but  in 
addition  speedwell, 
goosegrass,  plantain, 
black  bindweed, 
spurry,  sandwort, 
scarlet  pimpernel, 
toadflax,  and  may- 
weed were  well  repre- 
sented, and  a  few 
seeds  of  several  other 
species  were  also  pre- 
sent. In  a  few  weeds, 
as  bittersweet  (Sol- 
anum  dulcamara)  and 
black  nightshade  (S. 
nigrum],  seed  distri- 
bution by  birds  is 
ensured  by  special  at- 
tractions, the  seeds 
being  enclosed  in  juicy 
coloured  berries  which 
are  eagerly  devoured, 
and  many  later  ejected 
uninjured,  the  weeds 
thus  being  spread  far 
and  wide. 


FIG.  15. — HORSETAIL  (Equisctum  arvense). 

A.  Aerial  Shoot.  B.  Underground  Stem. 

C.  Rootlets. 


B.  Distribution  by  Vegetative  Parts  (  Vegetative  Reproduction]. 

(a)  By  Underground  Stems. 

(a*)  Creeping  Stems. — Some  of  the  weeds  that  are  most 
difficult  to  eradicate  are  provided  with  elongated    branching 


32  WEEDS  OF  FARM  LAND 

stems  that  creep  along  below  the  surface  of  the  ground. 
These  stems  do  not  bear  ordinary  leaves  but  are  usually 
clothed  with  thin  colourless  or  brown  scale  leaves  from  whose 


FIG.  16. — COUCH-GRASS  (Agropyron  repens}. 

A.  Aerial  Shoot.       B.  Creeping  underground  Stem.       C.  Sharp-pointed  Bud  on 

Underground  Stem. 

axils  branches  arise  that  grow  up  above  the  soil  and  develop 
the  usual  type  of  green  leaves.  The  underground  stems  serve 
as  carriers  whereby  the  new  aerial  shoots  are  taken  to  a  con- 
siderable distance  from  the  original  position,  so  extending  the 


DISTRIBUTION  OF  WEEDS 


33 


FIG.  17. — CORN  SOWTHISTLE  (Sonchus  arvensis). 

A.  Aerial  Shoot.  C.  Rootlets. 

B.  Creeping  Underground  Stem.  D,  Flower-head, 

3 


WEEDS  OF  FARM  LAND 


DISTRIBUTION  OF  WEEDS  ' 


35 


FIG.  19.— WOODWAX  (Genista  tinctoria). 
A,  Aerial  Shoot,        B,  Stout  woody  Underground  Stem. 


36  WEEDS  OF  FARM  LAND 

range  of  the  weed.  Rootlets  are  given  off  from  the  creeping 
stems,  and  if  the  latter  are  broken  up  every  small  piece  that 
bears  a  bud  or  young  shoot  is  capable  of  striking  root  for  itself 


5 


FIG.  20. — SORREL  (Rumex  acetosd).  • 

A.  Aerial  Shoot.  C.  Scars  of  old  Aerial  Shoots. 

B.  Thickened  Underground  Stem.  D.  Koots. 

and  forming  an  independent  plant.  In  bindweed  (Convolvulus 
arvensis)  (Fig.  13),  thistle  (Cirsium  arvense)  (Fig.  14),  horse- 
tail (Equisetum  arvense]  (F"ig.  1 5),  couchgrass  (Agropyron  rep  ens] 
(Fig.  1 6),  and  sheep's  sorrel  (Rumex  acetoselld]  (Fig.  38),  the 
underground  stem  is  fairly  thin,  but  in  corn  sowthistle 


DISTRIBUTION  OF  WEEDS 


37 


(Sonchus  arvensis]  (Fig.  17)  it  is  much  stouter,  while  in  colts- 
foot (Tussilago  farfara)  (Fig.  18)  it  is  sometimes  as  thick  as  a 
finger,  rather  fleshy,  and  may  strike  down  several  feet  into  the 
soil,  and  then  turn  horizontally  instead  of  creeping  just  below 
the  surface.1  As  branches  are  sent  up  at  frequent  intervals  a 


FIG.  21. — BULBOUS  BUTTERCUP  (Ranunculus  bulbosus). 

A.  Aerial  Shoot.  C.  Bud  from  which  new  Plant  will  arise. 

B.  Swollen  Base  of  Stem.  D.  Roots. 

single  coltsfoot  plant  is  capable  of  covering  a  very  large  area 
of  ground,  and  the  deep  driven  stems  are  exceedingly  diffi- 
cult to  eradicate.  Woodwax  (Gem's fa  tinctorid}  ,(Fig.  19) 
possesses  a  very  rugged  woody  underground  stem,  so  full  of 
"  snarls "  or  kinks  that  the  weed  cannot  be  removed  from 
pasture  land  by  any  means  less  heroic  than  ploughing  up. 

1  These  very  thick  stems  do  not  appear  in  the  specimen  illustrated. 


38  WEEDS  OF  FARM  LAND 

Sorrel  (Rumex  acetosd)  (Fig.  20)  is  also  provided  with  a  much 
thickened  stem,  which,  however,  grows  rather  slowly  and  sends 
up  aerial  shoots  at  frequent  intervals,  giving  the  whole  plant 
a  clustered  appearance. 

(/3)  Swollen  Stems. — In  some  plants  the  part  of  the 
stem  below  ground  is  swollen  into  a  kind  of  tuber  which  is 
reproduced  by  means  of  small  replicas  of  itself  formed  at 
the  base.  This  is  well  shown  by  bulbous  buttercup  (Ranun- 
culus bulbosus]  (Fig.  21),  and  a  very  similar  type  is  found  in 
pignut  (Conopodium  denudatum). 

(y)  By  Bulbs  and  Corms. — These  are  in  reality  swollen 
underground  stems  which  are  clothed  with  scale  leaves,  instead 
of  being  merely  the  swollen  bases  of  the  aerial  stems  as  in  y5. 
In  bulbs  the  stem  portion  is  at  the  base  and  is  much  flattened, 
giving  off  roots  below,  and  bearing  on  its  upper  side  a  number 
of  more  or  less  fleshy  scale  leaves  arranged  one  within  the  other. 
The  flowering  shoot  is  in  the  middle,  and  grows  up  above  the 
soil,  but  the  colourless  scale  leaves  remain  below  ground. 
The  only  well-known  farm  weeds  that  have  bulbs  are  wild 
onion  {Allium  vineale]  (Fig.  34),  ramsons  (Allium,  ursinutri) 
(Fig.  35),  and  spiked  star  of  Bethlehem  (Ornithogalum  pyren- 
aicum).  New  bulbs  are  developed  year  by  year  between  the 
scale  leaves,  arising  from  the  stem  portion,  and  as  several  may 
be  formed  from  one  bulb  the  spread  of  the  weed  is  rapid. 

In  corms  the  stem  portion  is  very  solid  and  occupies  most 
of  the  space.  It  is  covered  with  a  few  thin  chaffy  scale  leaves, 
quite  different  from  the  fleshy  scales  of  the  bulb.  The  general 
history  of  development  is  rather  similar,  new  corms  being 
formed  either  on  top  or  by  the  side  of  the  old  one,  the  latter 
in  this  case  perishing  at  the  end  of  the  year.  The  autumn 
crocus  (Colchicum  autumnale]  (Fig.  32)  is  probably  the  only 
common  farm  weed  characterised  by  this  method  of  re- 
production. 

(b)  By  Stems  Running  along  the  Surface  of  the  Ground. — 
In  such  weeds  as  bent  grass  (Agrostis  stoloniferd),  silverweed 
(Potentilla  anserind)  (Fig.  41),  mouse-ear  hawkweed  (Hieracium 
piloselld]  (Fig.  22),  creeping  cinquefoil  (Potentilla  reptans\  and 
creeping  buttercup  (Ranunculus  repens}  (Fig.  23),  long  thin 
stems  are  thrown  out  from  the  parent  plants.  These  run 
along  the  surface  of  the  ground,  and  at  intervals  develop  a 
tuft  of  leaves  and  a  number  of  rootlets.  The  latter  establish 
themselves  in  the  soil,  and  when  once  they  have  taken  hold 
the  young  plants  are  capable  of  leading  an  independent 


DISTRIBUTION  OF  WEEDS 


39 


existence.  Sooner  or  later  the  connecting  stems  may  perish ,  but 
they  often  persist  for  a  long  period,  so  that  a  single  plant  may 
cover  a  considerable  area  of  ground  as  the  same  process  of 
reproduction  goes  on  repeatedly.  The  conditions  of  the  habitat 
largely  determine  the  spread  of  these  weeds.  Under  some 
circumstances  the  runners  remain  short,  and  the  daughter  plants 
are  grouped  closely  round  the  parent,  but  in  others  the  runners 
are  lengthy  and  carry  the  plantlets  well  away,  thus  increasing 
the  area  of  spread  of  the  weed. 

(c)  By    Other    Types   of    Vegetative   Reproduction. — Some 
weeds  have  developed  very  specialised  types  of  reproduction 


FIG.  22. — MOUSE-EAR  HAWKWEED  (Hieracium  pilosella). 
A.  Runners  (above  ground). 

which,  though  less  common  than  the  two  preceding  classes, 
are  quite  effective  in  aiding  the  distribution  of  the  species. 

The  reproduction  of  the  wild  onion  (Allium  vineale]  by 
means  of  seeds  and  underground  bulbs  has  been  described, 
but  it  has  still  a  third  method,  as  the  flowering  heads  always 
carry  a  number  of  small  bulbils  at  the  base  of  the  flower  stalks. 
It  often  happens,  indeed,  that  the  flowers  are  entirely  absent, 
so  that  the  "  flower  head  "  consists  of  a  main  stalk  bearing 
aloft  a  cluster  of  small  bulbs.  These  ripen  and  fall  to  the 
ground,  where  they  start  into  growth  and  give  rise  to  new 
onion  plants.  It  is  largely  because  of  this  triple  method  of 
reproduction  that  the  wild  onion  is  so  difficult  to  exterminate. 

Onion    or  knotty  couch  (Arrhenatherum  avenaceum,  var. 


WEEDS  OF  FARM  LAND 


DISTRIBUTION  OF  WEEDS 


FIG.  24. — ONION  COUCH  (Arrhenatherum  avenaceum,  var.  tuberosum). 
A.  Swollen  Internodes.          B.  Leaves  from  Nodes  between  Swellings. 


42  WEEDS  OF  FARM  LAND 

tuberosum)  (Fig.  24)  is  a  variety  of  tall  oat  in  which  the  stem 
becomes  greatly  swollen  between  the  leaves,  giving  rise  to  a 
string  of  "  knots  "  with  leaves  springing  from  between  them. 
These  "  knots  "  are  very  tenacious  of  life,  and  each  is  capable 
of  developing  into  an  independent  plant.  It  has  been  sug- 
gested that  this  habit  of  growth  is  only  induced  by  special 
conditions  of  environment,  but  experiments  by  L.  M.  Under- 
wood l  at  Rothamsted  indicate  that  the  plant  is  a  genuine 
variety,  breeding  true  to  type  under  whatever  conditions  it  is 
grown  (see  p.  90). 

Most  of  the  farm  weeds  that  are  at  all  conspicuous  are  de- 
scribed above,  but  in  many  others  the  method  of  distribution 
is  not  sufficiently  striking  to  merit  inclusion  with  the  outstand- 
ing types.  Most  of  these  plants  are  dependent  upon  seeds  for 
their  reproduction,  though  some  spread  by  their  vegetative 
parts,  but  the  quantity  of  seed  produced  and  the  efficiency  of 
the  vegetative  reproduction  is  not  sufficient  to  bring  the  weeds 
into  prominent  notice  except  under  very  special  circumstances, 
when  from  one  cause  or  another  a  comparatively  insignificant 
weed  becomes  abundant  and  demands  attention. 

1  Underwood,  L.  M.  (1912),  "A  Note  on  Onion  Couch,"  Journ.  Ag.  S«., 
IV,  pp.  270-272. 


CHAPTER  III. 

PREVENTION  AND  ERADICATION  OF  WEEDS. 

Prevention. 

THE  harm  and  loss  caused  by  weeds  is  so  fully  recognised 
that  in  many  parts  of  the  world  legislation  is  in  force  to 
control  the  occurrence  and  spread  of  weeds,  the  laws  being 
both  preventive  and  remedial  in  nature.  In  many  cases  it 
is  an  offence  to  deal  in  agricultural  seeds  which  contain 
more  than  a  certain  minimum  percentage  of  specified  weed 
seeds,  and,  very  frequently,  certain  weeds  are  regarded  as 
noxious  and  must  be  either  eradicated  or  well  kept  under,  in 
default  of  which  severe  penalties  are  enforced.  The  Dominions 
and  several  European  countries  are  very  active  in  this  respect, 
but  up  to  the  present  little  action  has  been  taken  in  the  British 
Isles,  though  a  certain  amount  of  control  is  exercised  in  Ireland 
and  the  Isle  of  Man. 

In  those  countries  in  which  effective  action  is  taken  the 
power  of  control  conferred  by  legislation  is  very  elastic. 
Weeds  definitely  proclaimed  as  noxious  have  to  be  kept 
down  and  in  addition  local  authorities  may  proclaim  other 
weeds  as  circumstances  arise.  In  the  case  of  defaulters, 
the  authorities  are  given  power  to  have  the  work  carried 
out  and  to  claim  the  cost  from 'the  landowner  or  occupier, 
as  is  done  in  the  Transvaal,  Canada,  Australia,  and  else- 
where. Further  regulations  ensure  that  the  seed  imported 
from  abroad  shall  be  free  from  weed  seeds.  This  is  most 
essential,  as  in  parts  of  Australia  the  weed  flora  among  the 
arable  crops  on  cleared  land  consists  almost  entirely  of  alien 
weeds  imported  with  the  crop  seeds,  while  the  native  vegeta- 
tion has  entirely  died  out.  In  Canada,  too,  many  of  the  worst 
weeds  have  arrived  from  Europe  in  the  same  way.  So  far  no 
regulations  as  to  weed  control  are  existent  in  this  country,  and 
farmers  have  full  liberty  to  present  their  neighbours  with  un- 
limited supplies  of  the  seeds  of  thistles,  docks,  and  other  evil 

43 


44  WEEDS  OF  FARM  LAND 

weeds.  In  this  way  a  good  farmer  may  be  seriously  handi- 
capped if  he  has  a  careless  neighbour,  and  much  money  is  spent 
annually  for  labour  in  weeding  that  might  be  saved  if  some 
measure  of  legislative  control  were  introduced.  However,  the 
Testing  of  Seeds  Order,  IQI7,1  may  have  an  indirect  beneficial 
action  by  encouraging  farmers  to  harvest  their  crops  as  free 
from  weed  seeds  as  possible. 

Weeds  are  ubiquitous.  The  soil  is  full  of  seeds  awaiting 
opportunity  to  germinate ;  weed  seeds  lurk  in  hedges,  trees, 
farm  implements,  and  in  all  sorts  of  nooks  and  crannies  ;  wind 
carries  others  from  long  distances ;  water  and  animals  all  play 
their  part  in  distribution.  It  is  thus  obvious  that  it  is  impos- 
sible to  keep  any  farm  entirely  free  from  weeds,  but  neverthe- 
less a  great  deal  may  be  done  by  way  of  prevention.  The 
chief  preventive  measures  that  are  practicable  on  any  farm 
are  : — 

(1)  To  sow  clean  seed,  free  from  weed  seeds. 

(2)  To  prevent  any  weeds  from   forming  seed  and  so  re- 
producing themselves  in  that  way. 

(3)  To  clean  farm  machinery,   especially  if  borrowed,  to 
prevent  weed  seeds  being  carried  from  place  to  place. 

(4)  To    avoid    throwing  rubbish  from*  ricks,    barns,    and 
other  sources  on  to  arable  land. 

(1)  The  official  Seed  Testing  Station  is  prepared  to  ex- 
amine any  sample  of  agricultural  seeds  that  may  be  submitted 
and  to  report  on  the  nature  and  quantity  of  the  injurious  weed 
seeds  that  may  be  included,  in  addition  to  reporting  the  per- 
centage germination  and  purity  of  the  crop  seed  itself.     The 
Testing  of  Seeds  Order  requires  that  these  particulars  shall  be 
furnished  by  the  vendor  to  the  buyer  before  the  transaction  is 
completed,  so  that  the  onus  rests  on  the  purchaser  if  he  is 
foolish  enough  to  buy  seed  containing  a  total  of  more  than 
i  per  cent,  of  such  injurious  weed  seeds  as  docks  (Rumex  con- 
glomeratus,  Murr;  R.  obtusifolius,  L.  ;  R.  crispus,  L.),   sheep's 
sorrel  (R.  acetosella,  L.),  wild  carrot  (Daucus  carota,  L.),  York- 
shire fog  (Holcus  lanatus,  L.),  soft  brome  grass  (Bromus  mollis, 
L.  et  spp.\  suckling  clovers  (Trifoltum  dubium,  Sibth  ;   T.  pro- 
cumbens,  L.  ;  T.  parviflorum,  Ebrh,  and  T.  angulatum^  Waldst). 

(2)  In  order  to  prevent  weeds  from  forming  seed,  methods 
of  cultivation  suitable  to  the  particular  circumstances  should 
be  put  into  operation.     All    these  are    identical    with  those 
described  for  eradication   in  the  following  section,  but  they 

1  Testing  of  Seeds  Order  (1917),  Jour.  Bd.  Agric.,  XXIV,  pp.  1031-1039. 


PREVENTION  AND  ERADICATION  OF  WEEDS       45 

must  be  applied  early  enough  in  the  life  of  the  weeds  to  pre- 
vent any  danger  of  seed  formation  even  in  the  most  forward 
specimens.  So  much  seed  is  produced  by  individual  plants 
of  docks,  thistles,  poppies,  and  others  that  if  even  half  a  dozen 
plants  are  allowed  to  ripen  they  can  supply  sufficient  seed  to 
restock  a  large  area  the  following  year. 

(3)  Large  numbers  of  weed  seeds  are  carried  about  the 
country  by  agricultural  implements,  and  now  that  machinery 
of  larger  type,  that  passes  from  farm  to  farm,  is  coming  into 
common  use  the  danger  of  contamination  from  this  source  is 
increasing.     Steam   ploughs   and  cultivators,  motor  ploughs, 
and  other  types  of  machinery  tend  to  carry  about  clods  of 
soil  in  which  numerous  weed   seeds   are  buried.     Threshing 
machines,  binders,  wagons,  and  other  appliances  for  dealing 
with  the  harvested   crops  become  thoroughly  infested  with 
large   numbers   of  weed    seeds  and   these  are    carried    from 
place  to  place  unless  the  utmost  care  is  taken  to  keep  the 
machines  scrupulously  cleaned  out  after  use. 

(4)  Large  collections  of  weed  seeds  occur  at  the  bottom 
of  corn  and  hay  ricks,  in  barns  and  similar  places.     All  such 
rubbish  should  be  burned  if  possible,  or,  if  suitable  for  feeding 
animals,  may  be  steamed  or  thoroughly  ground  up  in  a  mill 
in  order  to  crush  the  weed  seeds  beyond  possibility  of  germina- 
tion.    This,  however,  is  hardly  feasible,  as  it  is  not  worth  the 
cost.     Too  often  this  source  of  infection  is  overlooked,  even 
on  farms  that  are  otherwise  well  protected  against  the  ingress 
of  weed  seeds,  and  much  damage  is  thereby  caused. 

Eradication. 

The  most  effective  measures  of  weed  prevention  are 
bound  to  fail  unless  a  constant  system  of  eradication  is  in 
force.  From  one  year's  end  to  another  it  is  possible  and 
necessary  for  the  farmer  to  be  combating  the  weeds,  so 
that  he  always  remains  master  and  never  lets  them  get  the 
upper  hand.  The  methods  of  eradication  are  many,  but  most 
of  them  can  be  summed  up  under  the  heads  of  eradication 
by  mechanical  and  by  chemical  means.  A  few  special 
methods  are  occasionally  used  which  cannot  quite  be  classified 
in  this  way,  but  these  are  the  exception  rather  than  the  rule. 

From  the  very  early  days  of  agriculture  cultivation  has 
been  regarded  as  the  principal  means  of  getting  rid  of  weeds. 
The  old  husbandman  knew  nothing  of  our  modern  agricultural 
machinery  and  carried  on  his  work  with  the  old-fashioned 


46  WEEDS  OF  FARM  LAND 

implements  worked  by  hand  and  animal  labour.  No  chemical 
substances  were  recognised  in  agriculture,  and  naturally 
enough  the  methods  employed  were  conservative  and  farmers 
did  not  foresee  future  improvements.  In  this  way  one  finds 
Blith1  stating  that  ploughing  is  the  only  cure  for  weeds, 
and  that  such  common  weeds  as  nettles,  docks,  chickweeds, 
and  hemlocks  (chevils  ?)  are  caused  as  much  by  over-rich  and 
fat  soil  as  by  anything  else.  Our  knowledge  has  advanced 
since  those  days,  the  true  cause  of  the  prevalence  of  weeds  is 
better  understood,  and  many  kinds  of  mechanical  and  chemical 
methods  have  been  devised  to  deal  with  them. 

The  system  under  which  land  is  farmed  has  much  to  do 
with  the  particular  methods  adopted  for  the  eradication  of 
weeds.  Methods  that  are  possible  and  effective  on  ploughed 
land  are  impossible  of  application  on  grass-land,  besides  which 
the  types  of  weeds  that  occur  under  the  two  systems  are  quite 
different.  It  will  therefore  be  necessary  to  make  a  sharp  dis- 
tinction and  to  consider  separately  the  methods  of  exter- 
minating weeds  on  arable  and  grass-land. 

I.  Eradication  of  Weeds  from  Arable  Land. 

(a)  Eradication  by  Methods  of  Cultivation — Mechanical 
Means. — The  primary  method  of  removing  weeds  from  arable 
land  is  ploughing,  for  unless  some  clearance  is  first  effected  in 
this  way  whatever  other  methods  of  cultivation  may  be  carried 
out  are  of  little  avail.  In  ploughing  the  surface  vegetation 
is  bodily  reversed  and  buried  under  a  mass  of  soil  which 
prevents  the  leaves  of  the  plants  having  access  to  the  light 
and  air  essential  to  them.  The  roots  are  cut  off  from 
communication  with  the  lower  soil,  and  in  this  position  the 
plants  are  subjected  to  baking  and  consequent  withering  if  the 
weather  be  hot,  or  if  it  be  wet  and  cold  the  crowns  are  sur- 
rounded with  so  much  dampness  that  they  rot  away.  This 
effectively  disposes  of  large  numbers  of  the  annual  weeds  that 
have  fibrous  roots,  while  the  top  growth  of  perennials  is 
also  destroyed.2  The  act  of  ploughing,  however,  breaks 
up  the  roots  or  the  underground  stems  of  the  perennials,  and 
unless  further  measures  are  taken  much  harm  may  result.  If 

1  Blith,  W.  (1652),  "  Survey  of  Husbandry  Surveyed". 

2  The    Russians    advocate   very   deep    ploughing   (12  inches  at   least)    as 
by  that  means  weed  seeds  are  buried  at  such  a  depth  that  they  cannot  grow. 
See  Anzibor,  S.  (1912),  Bull.  Bur.  Agric.  Intelligence  and  Plant  Diseases,  III, 
pp.  2313-4. 


PREVENTION  AND  ERADICATION  OF  WEEDS       47 

these  broken  pieces  are  left  in  the  soil  after  ploughing  the 
field  will  shortly  be  covered  with  far  more  of  the  perennial 
weeds  than  were  present  in  the  first  instance.  An  excellent 
instance  of  this  was  seen  by  the  writer  in  the  summer  of  1918 
on  a  neglected  farm  in  Suffolk.  The  arable  land  had  been 
getting  into  poor  condition  for  some  years,  and  in  1916  an 
attempt  was  made  to  work  some  of  the  fields  with  the  steam 
plough.  For  some  reason  no  after-cultivation  of  any  kind  was 
carried  out,  and  in  August,  1918,  it  was  covered  with  a  dense 
rank  herbage  consisting  almost  entirely  of  "  water  grass " 
(Agrostis  or  twitch),  together  with  an  army  of  curled  docks  that 
were  seeding  freely.  The  condition  of  the  land  thus  treated 
was  so  hopeless  that  even  the  farmers  of  the  neighbourhood, 
experienced  in  dealing  with  that  particular  type  of  soil,  con- 
fessed themselves  unable  to  tackle  the  problem  of  reducing  the 
chaos  to  a  semblance  of  order.  This  is  a  practical  demonstra- 
tion of  the  necessity  of  following  the  plough  with  other  imple- 
ments which  will  gather  up  the  fragments  of  perennial  weeds  in 
order  that  they  may  be  collected  and  destroyed.  Repeated 
harrowing  after  ploughing  serves  the  double  purpose  of  collect- 
ing these  weeds  and  of  reducing  the  soil  to  the  fine  tilth  most 
favourable  to  germination.  This  in  itself  is  a  valuable  aid  to 
weed  eradication.  The  soil  is  full  of  weed  seeds  and  the  good 
tilth  encourages  them  to  .germinate  rapidly,  and  it  is  an  easy 
matter  to  destroy  the  delicate  seedlings  by  further  cultivation, 
so  disposing  of  some  proportion  of  the  stores  of  buried  seeds. 
If  it  is  not  necessary  to  sow  the  crop  immediately  this  process 
can  be  repeated,  as  each  cultivation  of  the  surface  maintains 
a  good  seed  bed  for  the  germination  of  the  weeds. 

Even  after  the  crops  are  sown  and  are  well  through  the 
soil  it  is  possible  to  destroy  the  weed  seedlings  by  using  the 
appropriate  farm  implements.  Special  machines  have  been 
invented  to  meet  this  need,  and  the  Poppy  Destroyer  and  the 
American  Weeder1  are  but  two  of  the  various  types  employed. 
Among  some  crops  it  is  possible  to  run  the  horse-hoe,  but 
under  special  circumstances,  where  a  particular  weed  is  trouble- 
some and  labour  is  available,  the  surface  cultivation  is  carried 
out  with  the  hand-hoe.  When  the  crops  become  too  high  to 
admit  of  the  passage  of  any  cultivator  it  is  necessary  to 
resort  to  hand  pulling  for  the  removal  of  the  larger  weeds, 
and  if  necessary  the  hand-hoe  can  be  kept  going  for  some 
time  longer.  Large  individual  weeds,  as  thistles,  that  cannot 

1  Long,  H.  C.  (1910),  "  Common  Weeds  of  the  Farm  and  Garden,"  pp.  34-35. 


48  WEEDS  OF  FARM  LAND 

be  pulled  out  easily  should  be  constantly  spudded  in  order 
to  exhaust  the  underground  parts  as  much  as  possible.  Corn 
sowthistle  (Sonchus  arvensis)  is  one  of  the  weeds  that  require 
constant  attention.  It  should  be  cut  early  in  the  year  soon 
after  it  comes  above  ground,  and  the  cutting  should  be 
repeated  as  often  as  possible  during  the  season. 

After  the  weeds  have  been  collected  they  should  on  no 
account  be  allowed  to  lie  about  on  the  ground,  particularly  if 
they  are  approaching  the  flowering  stage.  Such  plants  as 
docks  and  thistles  have  such  large  stores  of  food  in  their 
underground  parts  that  if  they  are  far  enough  advanced 
it  is  in  many  cases  possible  for  them  to  continue  growing 
even  after  they  are  pulled  up  from  the  soil,  so  that  they 
can  ripen  and  shed  their  seed.  For  this  reason  the  ac- 
cumulation of  docks  and  thistles  in  heaps  in  the  hedgerows 
should  be  discountenanced.  All  weeds  and  parts  of  weeds 
should  be  burned  straightway  or  removed  from  the  field  and 
mixed  with  lime  to  rot  them  down  into  a  compost.  Even 
this  latter  proceeding  is  dangerous  if  seeding  is  at  all  advanced, 
as  many  seeds  have  such  a  hard  covering  that  they  fail  to 
rot,  and  even  though  they  are  buried  in  the  lime  they  are 
likely  to  remain  uninjured  in  the  compost  heap  ready  to 
spring  into  activity  when  the  manure  is  spread  on  the  land  and 
favourable  conditions  arise  for  germination. 

When  a  heap  of  manure  is  kept  for  any  length  of  time  and 
reaches  a  fairly  high  temperature  in  the  interior  it  is  probable 
that  many  weed  seeds  perish  from  the  heat  developed.  Some 
species  seem  proof  against  almost  any  adverse  circumstances, 
and  very  frequently  the  first  plant  to  spring  up  where  a  heap 
of  stable  manure  has  stood  is  knotgrass  (Polygonum  aviculare\ 
while  fat  hen  (Chenopodium  album}  grows  so  freely  upon  a 
manure  heap  that  it  is  often  called  mixen-weed  or  muck-weed. 

As  it  is  all-important  to  prevent  seeding  any  practicable 
method  should  be  adopted  to  avoid  it.  In  some  cases  wild 
radish  is  troublesome  and  is  too  abundant  to  be  pulled  out  by 
hand.  It  has  been  suggested x  that  when  it  occurs  among  corn 
crops  the  plants  should  be  "  topped"  with  a  scythe  at  the  time 
of  flowering  so  that  seed  formation  is  impossible. 

It  is  sometimes  advisable  to  reverse  the  order  of  working 
and  to  begin  to  effect  a  clearance  before  ploughing  is  done. 
This  is  specially  useful  after  dirty  crops  like  peas,  which  leave 
a  stubble  full  of  such  pests  as  couch-grass  and  twitch.  A 

^Jour.  Ed,  Agric.  (1908),  XIV,  p.  696. 


PREVENTION  AND  ERADICATION  OF  WEEDS       49 

heavy  harrow  run  over  the  stubble  will  drag  up  much  of  the 
weed,  and  if  the  latter  be  collected  into  heaps  and  burnt  there 
and  then  on  the  ground,  the  ashes  help  to  fertilise  the  soil  and 
the  land  is  more  fit  for  ploughing.  This  may  be  done  even  on 
heavy  land  when  "  running  grasses  "  are  a  nuisance.  On  light, 
sandy  land  this  is  the  recognised  method  of  dealing  with 
twitch,  as  at  every  available  opportunity  the  cultivator  is  run 
over  the  soil  to  gather  the  stuff  up  ready  for  burning. 

It  is  occasionally  possible  to  take  advantage  of  the  pre- 
ference of  weeds  for  certain  soils  in  order  to  eradicate  them 
or  to  prevent  them  from  being  spread  from  place  to  place. 
Sheep's  sorrel  (Rumex  acetoselld]  requires  soil  of  a  very  open 
and  light  nature,  and  anything  that  consolidates  the  soil  tends 
to  suppress  the  weed.  Anderson  (I/79)1  quotes  an  instance 
of  an  experiment  in  which  sheep's  sorrel  was  eradicated  by 
thoroughly  rolling  the  land.  Many  weed  seeds  are  carried 
about  in  farmyard  manure,  and  as  the  weeds  that  are  most 
abundant  on  heavy  land  differ  from  those  that  prefer  light  soil, 
Hardie  (1904)  2  suggested  th'at  wherever  possible  the  manure 
made  from  straw  grown  on  heavy  land  should  be  put  on  to 
light  land,  and  vice  versa,  and  then  the  weed  seeds  would 
have  less  encouragement  to  flourish  in  their  new  environment. 

The  methods  above  described  are  those  that  are  applicable 
to  arable  land  irrespective  of  the  crops  carried.  The  crop 
itself,  however,  can  be  used  as  a  valuable  instrument  in  weed 
eradication,  whether  on  account  of  its  habit  or  the  particular 
type  of  cultivation  it  requires.  Roots  are  most  valuable 
cleaning  crops,  and  are  often  sown  when  a  piece  of  land  has 
grown  so  foul  that  it  needs  special  treatment.  Most  root 
crops,  as  mangels,  swedes,  and  turnips,  are  sown  so  late  in  the 
season  that  a  long  time  is  available  in  the  spring  for  cultivat- 
ing and  clearing  the  land  of  weeds  as  described  above.  Then, 
when  once  the  crop  is  up,  it  needs  constant  attention  and 
cultivating  from  first  to  last.  The  horse-hoe  is  used  to  clear 
the  spaces  between  the  rows,  later  on  hand-hoeing  takes  place 
to  single  the  plants,  and  to  the  very  end  it  is  necessary  to 
keep  the  land  well  worked  if  a  good  crop  is  to  be  obtained. 
All  this  cultivation  and  working  of  the  soil  is  the  very  thing 
to  clear  the  weeds  out  of  the  way.  The  weed  seeds  find  a 
perfect  seed  bed  in  which  they  germinate,  only  to  be  cut  down 

1  Anderson,  J.  (1779),  "  Essays  on  Agriculture,"  Vol.  II,  pp.  215-226. 
a  Hardie,    W.    (1904),    "Destruction  of  Weeds   by   Surface   Cultivation," 
jfour.  Bd.  Agric.,  XI,  pp.  193-201. 

4 


36  WEEDS  OF  FARM  LAND 

at  the  next  stage  in  cultivation.  Fresh  seedlings  arise  to 
meet  with  the  same  fate,  and  very  few  plants  are  able  to 
reach  maturity  to  replenish  the  store  of  seed  in  the  soil.  Two 
root  crops  in  succession  will  make  a  wonderful  clearance  even 
on  badly  infested  land,  and  this  method  has  been  successfully 
used  in  getting  rid  of  shepherd's  needle  (Scandix pecten\  which 
is  troublesome  in  some  places.1 

A  totally  different  method  is  adopted  when  "  smother 
crops "  are  grown.  In  this  case  the  weed  and  crop  seeds 
start  into  growth  together,  but  before  long  the  crop  grows 
ahead  much  more  rapidly  than  the  weeds,  and  as  the  latter 
are  deprived  of  light  by  the  overshadowing  of  their  competitors 
they  are  killed  out  before  they  attain  any  size.  Clover, 
lucerne,  sainfoin,  and  mustard  are  among  the  more  common 
smother  crops.  Lucerne  is  particularly  effective,  because  it 
is  cut  so  often  during  the  season  that  all  the  weeds  that  grow 
are  cut  off  before  they  seed,  and  as  the  crop  occupies  the 
ground  for  several  years  a  good  clearance  is  effected.  Couch- 
grass  {Agropyron  repens]  has  beeli  effectively  dealt  with  in  this 
way.  In  a  French  test 2  vetches  were  sown  on  a  field  infested 
with  couch-grass  in  April,  1910,  and  a  good  hay  crop  was 
taken  in  July.  By  this  time  the  vetches  had  "  gone  down  "  and 
smothered  all  the  top  growth  of  weeds,  so  that  after  mowing 
the  field  was  clean  and  fit  for  sowing  lucerne  the  following 
spring.  Three  good  cuts  of  lucerne  were  obtained  in  191 1,  as 
the  couch  had  no  opportunity  of  asserting  itself  and  spoiling 
the  crop. 

When  crops  are  grown  for  silage  very  good  opportunities 
arise  for  clearing  the  land  of  weeds,  provided  the  ground  is 
broken  up  directly  the  crop  is  removed,  so  that  the  weeds  are 
foiled  in  any  attempt  to  reassert  themselves.3  The  silage  crop 
exhausts  the  soil  moisture  very  considerably,  and  if  the  ground 
is  ploughed  without  delay  the  weeds  rapidly  dry  up,  particu- 
larly if  the  piocess  is  favoured  by  hot,  dry,  summer  weather. 
It  is  usually  possible  to  carry  out  this  work  because  it  comes 
between  hay  and  corn  harvest,  when  more  time  is  available. 
The  perennial  weeds  are  not  exterminated  by  such  silage  crops 
as  oats  and  tares,  but  they  are  suppressed  for  a  time  and  so 
weakened  that  they  are  more  easily  dealt  with  in  other  ways. 

1  Long,  H.   C.  (1912),  "  Identification  and  Eradication  of  Some  Common 
Weeds,  IV,"  Jour.  Bd.  Agric.,  XIX,  pp.  273-277. 

2  La  Terre  Vaudoise  (1911),  No.  50,  p.  458. 

3 Amos,  A.  (1917),  "Some  Problems  in  the  Growth  of  Silage  Crops," 
Jour.  Bd.  Agric.,  XXIV,  pp.  167-168. 


PREVENTION  AND  ERADICATION  OF  WEEDS  '    51 

Some  weeds,  however,  seem  to  be  proof  against  all 
methods  of  eradication,  especially  if  they  occur  on  soil  to 
which  they  are  particularly  suited  and  where  they  normally 
grow  in  great  abundance.  Corn  marigold  (Chrysanthemum 
segetum)  tends  to  resist  all  attempts  to  remove  it.  In  one 
case,1  when  it  had  so  completely  destroyed  two  acres  of 
barley  that  harvesting  was  not  attempted,  the  land  was 
sown  down  to  green  crops  for  four  successive  years  with  no 
success.  This  weed  has  long  had  an  unenviable  reputation, 
for  even  in  1727  Threkeld  wrote,  "  Maunour  courts  do  amerce 
careless  tenants  who  do  not  weed  it  out  before  it  comes  to 
seed  ".  Some  success  may  be  obtained  by  growing  several 
successive  root  crops  on  infested  land,  provided  scrupulous 
care  is  taken  with  the  hoeing  so  as  to  allow  no  plant  to  seed. 
Older  writers  claim  that  manuring  with  chalk  is  effective.2 
This  weed  is  very  troublesome  in  turnip  fields  on  the  sandy 
soil  of  Norfolk. 

Wild  oats  is  a  bad  weed  in  some  districts  and  is  difficult 
to  get  rid  of.  Adam3  (1789)  claimed  that  it  could  be 
eradicated  by  putting  infested  land  down  to  clover  and  mow- 
ing the  oats  and  clover  together  before  the  oats  were  ripe. 
The  plant  is  annual,  so  the  roots  do  not  shoot  out  again,  and 
flowering  would  thus  be  prevented.  It  seems  doubtful 
whether  one  year  only  of  this  treatment  would  be  really  effec- 
tive. Observations  made  by  the  writer  in  Suffolk  seem  to  show 
that  wild  oat  seed  is  capable  of  lying  dormant  for  some  years, 
and  a  stock  of  ungerminated  seed  would  probably  remain 
ready  to  spring  up  after  the  removal  of  the  clover  crop.  Deep 
ploughing  of  land  infested  with  wild  oat  serves  to  bring  up  a 
large  stock  of  dormant  seeds  into  conditions  favourable  for 
germination.  Some  of  these  germinate  at  once  and  are 
cleared  away  if  thorough  surface  cultivation  is  carried  out. 
Most  of  the  seeds,  however,  bide  their  time  and  germinate 
among  succeeding  cereal  crops,  so  that  the  deep  ploughing 
really  encourages  an  increase  in  the  crop  of  wild  oats  in  future 
years ;  in  France  it  was  considered  that  the  deep  plough- 
ing carried  out  in  1912  favoured  the  invasion  of  this  pestilent 
weed  in  1913.* 

When  a  smother  crop  is  grown  it  is  of  course  necessary 

*Jour.  Bd.  Agric.  (1907),  XIV,  pp.  536-537- 
1 "  Gleanings  from  Agriculture"  (1802). 

3  Adam,  J.  (1789),  "  Practical  Essays  on  Agriculture,"  II,  pp.  173-198. 

4  Rabate",  E.,  "La  Folle  Avoine"  (1913),   Le  Progres  Agricole  e  Viticole, 
33,  No.  32,  pp.  116-180. 

4  * 


52  WEEDS  OF  FARM  LAND 

that  the  crop  seed  should  be  free  from  weed  seed.  This  can 
now  be  easily  assured  by  the  guarantee  that  must  be  issued 
with  all  seeds  sold,  but  hitherto  much  care  has  been  necessary. 
Cleavers  (Galium  aparine)  was  a  common  impurity  in  rape 
seed,  and  in  the  districts  bordering  the  North  Sea  it  was  usual 
to  clean  the  rape  by  running  the  seed  over  a  cloth,  when  the 
rape  rolled  off  while  the  cleavers  seeds  were  caught  by  the 
cloth  by  means  of  their  hooks.1 

When  all  other  methods  fail  two  more  drastic  treatments 
may  be  tried  :  the  land  may  either  be  fallowed  for  a  season  or, 
as  a  last  resort,  it  may  be  laid  down  to  grass  for  a  term  of 
years. 

Under  the  old  system  of  agriculture  fallowing  was  usu- 
ally regarded  as  an  integral  part  of  the  rotation  of  crops,  but 
with  improved  methods  of  cultivation  and  the  increased  use  of 
manures  it  is  now  less  generally  used  unless  for  such  a  specific 
purpose  as  clearing  land  of  specially  bad  weeds.  If  land  can 
be  kept  clean  without  a  bare  fallow  it  is  usually  more  profit- 
able to  keep  it  cropped  continuously,  partly  because  the  value 
of  the  extra  crop  is  obtained  and  partly  because  a  definite  loss 
of  nitrogen  has  been  proved  to  occur  when  soil  is  left  bare 
and  exposed  without  any  green  covering.  Under  some  cir- 
cumstances, however,  and  especially  on  heavy  land,  a  bare 
fallow  proves  the  most  effective  and  prompt  means  of  reduc- 
ing the  weeds.  For  this  purpose  the  land  should  be  ploughed 
and  harrowed  to  remove  as  many  weeds  as  possible,  and  then 
be  cultivated  to  provide  a  tilth  in  which  the  weed  seeds  in  the 
soil  may  be  encouraged  to  germinate.  Further  ploughings 
and  cultivations  must  be  carried  out  during  the  season,  the 
great  object  being  to  obtain  as  many  weed  seedlings  as  possible 
in  order  that  they  may  be  destroyed  forthwith.  It  is  essential 
that  the  intervals  between  the  cultivations  should  not  be  long 
enough  to  allow  any  of  the  weeds  to  seed,  and  careful  watch 
must  be  kept,  as  some  weed  species  flower  and  seed  with  great 
rapidity  under  all  circumstances  and,  if  the  season  be  dry,  the 
longer  lived  weeds  may  be  induced  to  hurry  on  their  seeding 
processes  on  account  of  the  drought.  Fallowing  may  be  par- 
ticularly effective  when  for  any  reason  a  succession  of  straw 
crops  has  been  carried  on  the  same  field.  The  Broadbalk  field 
at  Rothamsted,  which  has  carried  wheat  for  seventy-five  years, 
since  1843,  is  badly  infested  with  black  bent  (Alopecurus 
agrestis),  so  badly  that  constant  hoeing  and  hand  pulling  fail 

:  Jour.  Bd.  Agric.  (1912),  XIX,  p.  321. 


PREVENTION  AND  ERADICATION  OF  WEEDS       53 

to  keep  it  in  check.  Consequently  half  of  the  field  was  fallowed 
in  1914  for  a  season  and  the  other  half  in  1915,  and  the 
following  years  far  less  of  the  pest  was  in  evidence. 

When  all  other  means  of  eradication  fail,  whether  they  be 
methods  of  cultivation  or  "  chemical  "  means,  obstinate  weeds 
will  sometimes  disappear  if  the  land  be  laid  down  to  grass  for 
a  term  of  years.  Thin  was  fully  recognised  in  the  eighteenth 
century,  and  is  still  practised  when  necessary  at  the  present  day. 

Anderson1  (1779)  noticed  that  couch-grass  and  knotgrass 
only  occur  while  the  land  is  under  cultivation,  or  at  most  for  a 
year  or  two  after  it  is  laid  down  to  grass,  "  after  which  they 
usually  disappear  and  are  no  longer  seen  till  the  land  has  been 
again  in  tillage  for  some  time.  And  it  is  in  this  way  alone 
that  the  farmers,  in  some  of  the  worst  cultivated  parts  of  Scot- 
land, know  how  to  get  rid  of  these  destructive  weeds." 

Adam  2  (1789)  claimed  that  to  extirpate  coltsfoot  (Tussilago 
farfara]  thoroughly  the  land  must  be  long  laid  down  to  grass, 
though  he  admitted  that  it  was  once  almost  destroyed  by  two 
successive  crops  of  vetches,  and  that  it  may  be  killed  by  allow- 
ing the  land  to  lie  for  a  sufficient  time  under  clover  and  ryegrass. 

Most  excellent  results  have  been  obtained  by  an  adaptation 
of  this  method  in  recent  years  in  dealing  with  wild  onion 
(A Ilium  vineale).  This  is  only  troublesome  on  heavy  soil, 
but  is  sometimes  so  abundant  as  to  ruin  the  crops,  and  no 
ordinary  method  is  effective  in  reducing  it.  The  plant  spreads 
in  three  ways,  by  means  of  seeds,  by  bulbils  formed  in  the 
flowering  head,  and  by  "offsets"  from  the  subterranean  bulb. 
Experiments  were  carried  out  at  the  Woburn  Experimental 
Station  3  and  also  on  fields  at  Woburn  and  Chelsing  in  which 
the  pest  was  very  abundant.  Many  chemical  treatments  were 
tried,  with  little  or  no  success  in  most  cases,  and  various 
mechanical  treatments,  such  as  cutting  off  the  flowering  heads, 
pulling  up  plants  by  hand,  deep-ploughing  the  land,  and 
burning  the  soil,  were  equally  unsuccessful.  Experiments 
in  which  the  soil  was  lightened  by  mechanical  addition  were 
more  promising,  indicating  that  if  the  land  could  be  opened 
up  and  more  effective  drainage  provided  the  weed  might 
eventually  be  got  under.  It  was  therefore  decided  to  sow 
plots  down  with  "  Elliott's  mixture,"  a  mixture  of  grass 

1  Anderson,  J.  (1779)  (3rd  edition),  "  Essays  on  Agriculture,"  II,  p.  38. 

<2Adam,  J.  (1789),  "Practical  Essays  on  Agriculture— On  Weeds,"  pp. 
173-198. 

3Voelcker,  J.  A.  (1911),  "Eradication  of  Wild  Onion,"  Jour.  Roy.  Ag. 
Soc.,  72,  pp.  404-409. 


54  WEEDS  OF  FARM  LAND 

seeds  with  some  deep-rooted  plants  such  as  chicory,  burnet 
and  kidney  vetch,  since  the  latter  send  down  large,  strong 
roots  which  open  and  aerate  the  land.  Great  success  re- 
warded the  attempt.  At  the  end  of  six  years  th^  plots  of 
grass  from  Elliott's  mixture  were  ploughed  up,  and  after 
the  most  careful  search  hardly  a  single  onion  was  to  be 
found,  while  the  adjacent  plots  were  so  smothered  with  bulbs 
and  green  tops  that  they  gave  the  land  a  distinctly  white  ap- 
pearance. Further  experiments  were  made  on  the  infested 
area  to  compare  the  effect  of  a  cheaper  grass  mixture,  contain- 
ing only  Italian  ryegrass  and  red  clover,  with  that  of  the 
more  expensive  "  Elliott's  mixture ".  When  the  land  was 
ploughed  up  in  1916  l  it  was  found  that  the  cheaper  mixture, 
.in  which  deep-rooted  plants  were  absent,  had  been  far  less 
effective  in  eradicating  the  wild  onion,  while  the  Elliott's  mix- 
ture had  brought  about  a  complete  clearance. 

When  land  is  laid  down  to  grass  for  the  purpose  of  weed 
eradication  it  is  necessary  to  keep  the  pasture  down  for  a 
sufficient  number  of  years  in  order  that  the  underground  parts 
of  the  perennial  weeds  may  have  time  and  opportunity  to 
rot  away.  Such  a  clearance  is  not  effected  in  a  year  or  so, 
but  if  it  is  to  be  thorough  takes  some  considerable  time. 
Meanwhile  the  land  will  be  producing  hay  crops  and  so  will 
not  be  running  at  a  loss. 

(£)  Eradication  by  Spraying  and  Manuring. — Chemical 
Means. — During  the  past  few  years  many  attempts  have  been 
made  to  combat  weeds  by  various  chemical  means,  the  great 
object  being  to  find  some  application  which  will  destroy  the 
weeds  without  injuring  the  crop.  A  considerable  measure  of 
success  has  attended  the  experiments,  but  the  natural  con- 
servatism of  farmers  has  up  to  the  present  prevented  the  new 
methods  from  being  widely  adopted,  though  some  headway  is 
being  made. 

The  great  factor  that  makes  for  success  in  this  chemical 
treatment  lies  in  the  difference  between  the  habit  of  most 
weeds  and  that  of  such  crops  as  cereals.  The  long,  narrow 
upstanding  leaves  of  cereals,  which  are  often  covered  with 
"  bloom,"  tend  to  throw  off  rapidly  any  moisture  that  falls 
upon  them,  with  the  result  that  even  if  they  are  treated  with 
a  poisonous  or  corrosive  substance  injury  does  not  necessarily 
follow.  The  majority  of  weeds,  however,  have  broad  leaves 

^oelcker,  J.  A.,  "Occasional  Notes"  (February,  1918),  Roy.  Ag.  Soc., 
No.  4,  pp.  1-3. 


PREVENTION  AND  ERADICATION  OF  WEEDS       55 

which  stand  out  at  an  angle  from  the  stem,  retain  moisture 
long  enough  to  allow  any  poisonous  agent  to  become  effective. 
This  is  particularly  the  case  if  the  leaves  are  rough  or  crinkled, 
as  the  irregularities  hold  the  moisture  for  a  longer  time.  It 
is  more  difficult,  and  often  impossible,  to  apply  chemical 
methods  for  the  eradication  of  weeds  among  leguminous  crops, 
as  the  broader  leaves  of  clover,  trefoil,  sainfoin,  serradella  and 
others  behave  like  the  leaves  of  weeds,  and  hold  the  chemicals 
long  enough  to  cause  serious  injury  to  the  plant. 

With  root  crops  the  constant  cultivation  carried  on  is 
usually  sufficient  to  keep  weeds  in  check,  so  that  as  a  rule 
it  is  only  cereals  that  are  dealt  with  by  chemical  means. 

The  success  of  the  chemical  eradication  of  weeds  is  to 
some  extent  dependent  upon  the  weather.  It  is  essential 
that  the  substance  employed  should  remain  upon  the  leaves 
long  enough  to  come  into  action,  and,  therefore,  if  heavy  rain 
falls  immediately  after  an  application  much  of  the  benefit  is 
lost.  Consequently  it  is  necessary  to  watch  the  weather 
carefully,  and  if  unfortunately  rain  supervenes  too  soon,  the 
application  should  be  repeated.  Again,  if  a  dry  substance  is 
employed  it  would  easily  be  blown  away  if  applied  when  the 
leaves  were  dry,  so  in  this  case  it  is  usual  to  carry  out  the 
work  when  the  plants  are  wet  with  dew,  as  by  that  means  the 
chemical  is  fastened  to  the  leaves  and  does  not  tend  to  blow 
away  when  they  dry. 

The  chemical  substances  used  as  weed  killers  can  be 
divided  into  two  groups  : — 

(1)  Chemicals  that  merely  destroy  the  weeds  and  have  no 
direct  beneficial  action  upon  the  growth  of  the  crops.     These 
substances  are  usually  applied  in  the  liquid  form  as  sprays. 

(2)  Compounds  that  not  only  destroy  the  weeds  but  also 
exercise  a  manurial  action,  thus  directly  benefiting  the  crop  at 
a  later  date.     These  substances  are  usually  very  finely  ground 
manures,  and  are  applied  as  dry  powders  when  the  leaves  are 
damp. 

(i)  Sprays. — Most  of  these  are  corrosive  in  nature,  and 
burn  up  the  delicate  tissues  of  the  leaves  and  stems,  either 
killing  the  weeds  outright  or  so  crippling  them  that  the  crop 
is  able  to  get  well  ahead  before  the  weeds  can  again  start  into 
growth  to  any  extent.  These  chemicals  are  always  applied 
in  solutions  of  various  strengths.  Copper  sulphate,  iron  sul- 
phate and  sulphuric  acid  are  the  most  general  sprays,  but 
various  other  soluble  substances  have  been  tested, 


56  WEEDS  OF  FARM  LAND 

Copper  Sulphate. — This  is  probably  the  most  familiar  of 
all  weed  sprays,  and  has  been  experimented  with  for  years. 
It  is  most  generally  associated  with  the  destruction  of  char- 
lock (Brassica  sinapis],  but  its  use  has  been  extended  to  other 
weeds.  The  rough  crinkled  leaf  of  charlock  makes  it  a  most 
favourable  subject  for  eradication  by  spraying,  and,  given 
suitable  weather,  the  treatment  rarely  fails  to  make  a  consider- 
able reduction.  It  is  usually  best  to  spray  when  the  weeds 
are  small,  with  three  or  four  well-developed  leaves,  but  under 
favourable  conditions  success  will  often  attend  much  later 
spraying.  On  a  farm  in  Gedling,  Notts,  a  few  years  ago 
charlock  was  successfully  sprayed  when  in  full  flower,  but  this 
practice  is  not  one  to  be  recommended.  On  the  same  farm 
it  was  noticed  that  while  most  of  the  charlock  succumbed  a 
number  of  plants  remained  uninjured  :  closer  investigation 
showed  that  the  latter  were  a  different  species,  Brassica  cam- 
pestris,  which  has  smooth,  rather  waxy  leaves,  off  which  the 
spray  rolled  without  exercising  its  corrosive  action.  Various 
experiments  indicate  that  the  best  strength  to  use  is  4  or  5 
per  cent.  (4  or  5  Ib.  copper  sulphate  in  10  gallons  of  water), 
applied  at  the  rate  of  about  40  gallons  per  acre.  In  some 
cases  a  3  per  cent,  solution  is  effective,  but  only  under  specially 
favourable  conditions.1 

A  5  per  cent,  solution  of  copper  sulphate  at  the  rate  of 
50  gallons  per  acre  is  useful  for  eradicating  spurry  and  does 
its  work  thoroughly,  but  a  weaker  strength,  3  per  cent,  is  only 
partially  effective  and  allows  about  half  the  weed  crop  to  form 
and  ripen  its  seeds.2  3  In  the  latter  case  the  spurry  is  injured 
and  checked  at  first,  as  the  shoots  shrivel  and  become  brown 
at  the  tips,  but  later  on  many  plants  recover  considerably. 
This  recovery  is  prevented  by  the  use  of  the  5  per  cent,  solu- 
tion. Poppies  are  sensitive  to  this  spray,  and  even  a  2  per 
cent,  solution  does  them  harm.  It  has  been  suggested  that 
two  applications  of  a  3  per  cent,  solution,  with  an  interval  of  a 
few  days,  might  prove  quite  effective  in  eradicating  them.4 

In  some  cases  the  action  of  the  corrosive  spray  is  strength- 

J"  Charlock  Destruction"  (1909),  Bull.  I,  Agric.  Dept.,  Univ.  Coll.,  N. 
Wales,  Bangor. 

2 "Spraying  of  Charlock  and  Spurry"  (1908),  Bull.  II,  Agric.  Dept., 
Univ.  Coll.,  N.  Wales,  Bangor. 

3 "  Destruction  of  Spurry  in  Corn"  (1906),  Bull.  IX,  Agric.  Dept.,  Univ. 
Coll.,  N.  Wales,  Bangor. 

4"A  Common  Weed— The  Poppy"  (1909),  Jour.  Bd.  Agric.  XVI,  pp. 
26-31. 


PREVENTION  AND  ERADICATION  OF  WEEDS       57 

ened  by  the  addition  of  a  soluble  manure,  which  acts  as  a 
stimulant  and  enables  the  crop  to  get  ahead  of  the  weeds  before 
any  that  may  survive  have  time  to  recover.  Corn  butter- 
cup (Ranunculus  arvensis),  if  very  strong,  is  only  burnt  and 
not  destroyed  by  a  fairly  strong  solution  of  copper  sulphate, 
4|  per  cent  In  one  experiment1  the  amount  of  chemical 
was  more  than  doubled,  to  9-9  per  cent,  and  22  Ib.  of 
sodium  nitrate  was  added  to  the  10  gallons  of  water.  About 
35  to  40  per  cent,  of  the  weeds  were  killed  or  injured,  and  before 
the  rest  could  make  much  growth  the  wheat  had  benefited  so 
much  by  the  nitrate  that  it  pulled  right  ahead  of  the  weeds. 
Such  strong  applications  of  copper  sulphate,  however,  need 
very  careful  handling,  and  are  not  to  be  advised  under  ordinary 
circumstances. 

Iron  Sulphate. — In  most  cases  this  can  be. used  as  a  sub- 
stitute for  copper  sulphate,  and  very  often  the  iron  compound 
is  the  more  effective  of  the  two,  provided  that  suitable  strengths 
are  employed,  as  stronger  concentrations  of  the  iron  salt 
are  necessary.  It  has  been  largely  used  abroad  to  eradicate 
charlock,  and  experiments  have  also  been  carried  out  in  this 
country.  Quite  good  results  have  been  obtained  with  40 
gallons  of  7  per  cent,  solution  per  acre,  particularly  on  oat 
crops.  It  was  found  that  copper  sulphate  caused  the  young 
oats  to  flag  more  than  the  iron  sulphate,  but,  on  the  contrary, 
young  barley  received  more  initial  check  from  the  latter  spray. 
Hiltner2  used  a  far  more  concentrated  solution  in  larger 
quantities,  applying  53  gallons  per  acre  of  a  22  per  cent, 
solution  to  infested  oats.  Excellent  results  were  obtained, 
and  the  yield  of  oats  from  a  plot  treated  thus  was  six  times 
that  from  an  untreated  plot.  Care  was  taken  that  the  plants 
were  completely  dry  before  the  spraying  was  done,  and  the 
drastic  effects  on  the  charlock  were  visible  within  two  days. 
The  German  Agricultural  Society  3  recommend  the  addition 
of  5'  per  cent,  of  molasses  to  cause  the  solution  to  adhere  to 
the  weeds  more  firmly.  Iron  sulphate  may  also  be  applied 
dry  as  a  fine  powder,4  at  the  rate  of  3  to  4  cwt  per  acre.  It 

1  Martin,  J.  B.  (1916),  C.R.  de  V Academic  d?  Agriculture  de  France,  II,  pp. 
420-424. 

2  Hiltner    (1911),    Praktische  Blatter  fur  Pflanzenbau^und  Pflanzenschutz, 
Jan.,  Feb.,  Summ.  in  Jour.  Bd.  Agric.,  XVIII,  pp.  41-42. 

3  Mitt,  der  deut.  Landw.  Gesell.  (1911),  Flugblatt,  No.   n,  Summ.  in  Jour. 
Bd.  Agric.,  XVIII,  p.  244. 

4  Bull.  Soc.  Nat.  d"1  Agric.  (1909),  No.  5,  Summ.  in  Jour.  Bd.  Agric.,  XVI, 
p.  761. 


58  WEEDS  OF  FARM  LAND 

may   be   broadcasted    or  scattered   by  machine  early  in  the 
morning  while  the  leaves  are  still  wet  with  dew. 

All  cereal  crops,  and  also  the  leguminous  crops  sown 
among  them,  will  resist  dusting  or  spraying  with  iron  sulphate. 
The  leguminous  plants  owe  their  immunity,  in  this  case,  to 
the  fact  that  they  are  to  a  great  extent  protected  by  the  larger 
growing  weeds  and  the  cereals,  so  that  comparatively  little  of 
the  spray  reaches  their  leaves.  Serradella,  however,  growing  by 
itself,  will  not  stand  spraying  with  any  dilution  of  iron  sulphate 
or  at  any  stage  of  growth,  so  that  it  has  proved  impossible  to 
use  this  means  of  eradicating  wild  radish  among  this  crop. 
Nearly  all  unprotected  broad-leaved  crops  growing  alone  suffer 
badly,  and  beans,  vetches,  yellow  and  white  lupins,  roots  and 
potatoes  are  much  injured  by  the  iron  sulphate,  though  peas 
and  blue  lupins  are  rather  less  sensitive. 

The  iron  spray  is  more  effective  than  the  copper  salt  in 
dealing  with  poppies  and  corn  buttercups,  a  I  5  per  cent,  solu- 
tion reducing  the  weeds  drastically.  For  the  buttercup  the 
spray  is  best  applied  at  the  beginning  of  February,  and  a  1 5 
per  cent,  solution  may  be  used  as  this  is  known  to  do  no 
permanent  harm  to  the  cereal  crops. 

Sulphuric  Acid. — This  is  the  most  corrosive  agent  that  is 
used  in  the  eradication  of  weeds.  It  attacks  metals  violently, 
including  copper  ;  therefore  it  is  necessary  to  use  special  spray- 
ing machines  and  to  wash  them  out  thoroughly  immediately 
after  use  to  prevent  them  from  being  eaten  away.  Italian  ex- 
periments indicate  that  if  spraying  is  done  at  the  right  time  the 
production  of  the  cereal  crop  is  not  affected.  For  wheat  it 
should  be  used  during  February  and  early  March,  when  the 
plants  have  five  or  six  leaves,  at  the  rate  of  about  90  to  ico 
gallons  per  acre  of  an  8  or  10  per  cent,  solution  made  up  with 
water.  This  method  has  been  used  in  France,  in  Lot-e-Garonne, 
for  destroying  wild  radish.1  Sulphuric  acid  does  not  act  as  a 
universal  weed  destroyer,  as  all  the  weed  grasses,  including 
wild  oat  (Avena  fatud],  resist  its  action  because  their  habit 
resembles  that  of  the  cereals.  Medicks  (Medicago  spp.)  and 
members  of  the  lily  family  (as  wild  onion)  also  escape.  The 
acid  is  deadly  to  most  annual  and  biennial  weeds,  such  as 
poppy,  charlock,  corn  buttercup,  cornflower,  wild  carrot,  wild 
radish,  vetches  and  vetchlings,  and  it  clears  badly  infested 

1Rabatd,  E.  (1911),  "Destruction  des  Ravenelles  par  1'acide  sulfurique," 
Jour,  d1  Agriculture  pratique,  No.  13,  pp.  407-409. 


PREVENTION  AND  ERADICATION  OF  WEEDS       59 

fields  of  these  pests  very  effectively.1  For  oats  it  is  advisable 
to  use  about  60  to  70  gallons  of  the  10  per  cent,  solution  per 
acre,  and  rather  less  for  barley.2 

Arsenite  of  Soda. — The  very  poisonous  nature  of  this 
substance  has  prevented  it  from  coming  into  general  use  for 
spraying  purposes,  and  as  it  also  has  certain  effects  upon  the 
soil  it  needs  handling  with  much  judgment  It  is  widely  used 
in  rubber  plantations  in  Hawaii  and  among  sugar  canes  in 
Australia,  and  in  the  latter  case  it  is  claimed  that  its  use  has 
reduced  the  cost  of  weed  destruction  by  2  5  per  cent.3  Arsenite 
of  soda,  like  most  caustic  sprays,  cannot  be  used  on  the  broad- 
leaved  crops  without  injuring  them.  In  one  attempt  to  rid 
alfalfa  of  dodder  by  this  means  the  alfalfa  was  killed  as  well 
as  the  dodder.  Besides  this,  there  is  danger  of  poisoning  stock 
if  a  fodder  or  hay  plant  is  sprayed  with  too  much  of  it.  The 
spray  considerably  alters  the  mechanical  condition  of  the  soil, 
acting  as  a  deflocculating  agent.  It  is  strongly  fixed  by  the 
soil  and  is  not  washed  out  even  by  very  heavy  rains,  and  con- 
sequently it  is  liable  to  remain  for  an  indefinite  time  in  the  top 
few  inches.4  For  this  reason  it  is  unwise  to  use  the  sodium 
arsenite  spray  too  freely,  as  it  may  accumulate  in  the  surface 
soil  in  sufficient  quantity  to  act  as  a  poison  to  any  crop  that  is 
planted.  With  due  care,  however,  and  with  particular  crops, 
there  is  no  doubt  that  this  spray  is  decidedly  efficacious. 

Various  Sprays. — In  view  of  the  difficulty  in  obtaining 
some  of  the  more  usual  chemical  sprays,  such  as  copper  and  iron 
sulphate,  various  experiments  have  been  made  with  other 
promising  substances.  At  Rothamsted  charlock  plants  in 
various  stages  of  growth  were  sprayed  with  3  per  cent,  solutions 
of  nickel  sulphate  and  copper  sulphate  to  contrast  the  effect  of 
the  two.  With  young  plants  the  nickel  spray  was  much  slower 
in  taking  effect  than  the  copper  spray,  but  at  the  end  of  six 
days  all  the  plants  were  dead  and  made  no  recovery.  With 
6  per  cent,  solution  the  action  was  rather  more  rapid.  Later 
on  some  very  large  plants  just  coming  into  flower  were  sprayed 
in  a  similar  way,  but  although  a  few  days  afterwards  the 

1  Morettini,  A.  (1915),  Le   Stazioni   sperimentali  agrarie  italiane,  XL VIII, 
pp.  693-716. 

2  Jaguenaud,  G.  (1912),  "  Sur  la  destruction  des  mauvaises  herbes  dans  les 
Cereales  par  1'acide  sulfurque,"  Le  Progres  Agricole  e  Viticole,  29,  pp.  332-334. 

3"  Weed-killing  by  Machinery  "  (1916),  Queensland  Agric.  your.,  V,  Part  2, 
p.  61. 

4  McGeorge,  W.  T.  (1915),  Hawaii  Agric.  Expt.  Station,  Honolulu,  Press 
Bull.,  No.  50, 


60  WEEDS  OF  FARM  LAND 

leaves  were  badly  burnt  by  both  sprays,  the  plants  as  a  whole 
were  not  wilting  or  dying  off.  Probably  a  stronger  solution 
would  have  been  more  effective  at  this  stage,  but  the  results 
suggest  that  the  nickel  sulphate  would  prove  to  be  an  effective 
substitute  for  copper  sulphate,  though  it  might  be  necessary 
to  use  it  in  somewhat  greater  concentration  to  hasten  its 
action. 

Potassium  chloride  in  a  2Oto3O  per  cent,  solution  has  proved 
effective  in  destroying  charlock,  as  the  plants  touched  by  the 
liquid  are  completely  shrivelled  up.  When  the  substance 
can  be  obtained  more  cheaply  than  at  present  it  might  well 
be  given  a  further  trial,  as  the  potash  is  a  most  valuable 
manure  and  would  be  beneficial  in  this  way  after  the  initial 
work  of  weed  destruction  was  over.  The  potassium  chloride 
has  no  bad  effect  on  the  cereals,  and  may  be  used  at  the  rate 
of  352  Ib.  dissolved  in  1092  gallons  of  water  per  acre.1 
Strictly  speaking,  this  substance  comes  under  the  head  of 
manures,  but  as  for  the  purpose  of  weed  destruction  it  is 
applied  as  a  spray  it  is  more  conveniently  dealt  with  here. 

In  some  places  sodium  bisulphate  can  be  readily  obtained 
from  the  powder  works  at  a  cheap  rate,  and  in  parts  of  France 
farmers  have  been  able  to  get  it  in  truck  loads  of  5  or  10 
tons  at  the  rate  of  9^d.  per  220  Ib.  free  on  rail.  It  is  a 
most  effective  weed  killer,  resembling  sulphuric  acid  in  its 
action,  but  it  needs  less  precautions  in  its  use.  80  gallons 
per  acre  of  45  per  cent,  solution  (i.e.  360  Ib.  of  bisulphate  per 
acre)  are  recommended  for  use  if  the  fields  are  badly  infested 
with  weeds.2  The  stuff  is,  however,  difficult  to  handle,  so 
that  full  advantage  is  not  taken  of  its  availability. 

(2)  Manures. — The  method  of  eradicating  weeds  by 
applications  of  finely  ground  manure  is  not  very  widely  used, 
as  few  substances  are  yet  known  to  be  effective,  but  in  recent 
years  a  good  deal  of  work  has  been  done  in  this  direction 
with  calcium  cyanamide  (lime  nitrogen)  and  kainit. 

Calcium  Cyanamide. — Since  the  introduction  of  calcium 
cyanamide  as  a  commercial  manure  the  Germans  have  been 
using  it  to  a  considerable  extent  for  destroying  charlock  and 
wild  radish.  Numerous  experiments  have  demonstrated  that 
it  is  quite  efficient  for  this  purpose,  provided  that  it  is  applied 
when  the  plants  are  small  and  while  the  leaves  are  damp. 

1  Dusserre,   C.    (1916),  Travaux  de   Chimie  alimentaire  et  d'Hygiene,  VII, 
PP.  357-358. 

2  Feuille  ^information  du  Ministere  de  V Agriculture  (1918),  XXIII,  No.  8. 


PREVENTION  AND  ERADICATION  OF  WEEDS       61 

In  German  experiments  the  dressings  used  for  charlock  varied 
from  90  to  135  Ib.  per  acre,1  though  in  one  experiment  good 
results  were  obtained  with  only  60  Ib.  per  acre.2  In  some 
cases  the  cereal  crops  were  said  to  turn  rather  yellow  for  a 
few  days  after  application,  but  they  rapidly  recovered,  and, 
benefiting  by  the  nitrogen  in  the  manure,  gave  bigger  crops 
than  when  no  calcium  cyanamide  was  used.  Thistles  were 
also  very  susceptible  and  were  eradicated  along  with  the 
charlock.  On  the  other  hand,  in  experiments  carried  on  in 
North  Wales,3  calcium  cyanamide,  at  the  rate  of  80  and  120 
Ib.  per  acre,  had  no  permanent  effect  on  charlock  nor  on  the 
crop,  and  all  the  weeds  recovered  from  the  temporary  check 
they  received. 

Good  results  are  reported  to  have  been  obtained  by  treat- 
ing wild  radish  with  I  cwt.  calcium  cyanamide  per  acre,  but 
it  is  best  to  apply  a  heavier  dressing  if  the  weed  is  very 
abundant.  In  one  case  1 50  Ib.  per  acre,  applied  at  the  end 
of  April,  completely  destroyed  the  radish,  but  the  associated 
oat  crop  was  eight  days  later  in  maturing  on  account  of  the 
heavy  nitrogenous  manuring.  The  yield  of  oats,  however, 
was  half  as  much  again  as  that  from  the  control  plots  that 
had  been  left  untreated,  the  net  profit  from  the  use  of  calcium 
cyanamide  being  £2  153.  per  acre.4  Lime  nitrogen  is  also 
effective  against  poppies. 

Kainit — Kainit,  at  the  rate  of  4  to  8  cwt.  per  acre,  is  said 
to  be  quite  useful  in  the  suppression  of  charlock,  and  also  in 
the  eradication  of  many  other  weeds,  frequently  being  more 
effective  than  either  calcium  cyanamide  or  iron  sulphate. 
Heavier  dressings  are  also  recommended,  from  10  to  1 6  cwt. 
per  acre.  The  kainit  needs  to  be  very  finely  ground  and 
should  be  sprinkled  on  the  plants  when  they  are  wet  with  dew 
or  rain,  if  possible  on  the  morning  of  a  fine  day.  For  autumn 
sown  cereals  the  best  time  of  application  is  February  or  March, 
for  spring  sown  corn  the  manure  should  be  spread  soon  after 
the  seeds  have  germinated.  On  very  heavy  land  it  may 
be  necessary  to  apply  a  dressing  of  lime  to  prevent  undue 

1Deutsch.  Landw .  Presse.  (4th  Nov.,  1908),  Summ.  in  your.  Bd.  Agric.,  XV, 
p.  776;  (2ist  Jan.,  1914),  Summ.  in  your.  Bd.  Agric.,  XXI,  p.  64. 

2  Mitt,  der  deutsch.  Landw.  GeselL  (2Oth  July,  1907),  Summ.  in  Jour.  Bd. 
Agric.,  XIV,  p.  568. 

3  "Charlock  Destruction"  (1909),   Bull.  I,  Agric.   Dept.,  Univ.  Coll.,  N. 
Wales,  Bangor. 

4 Deutsch.  Landw.  Presse.  (24th  Aug.,  1912),  Summ.  in  Jour.  Bd.  Agric., 
XX,  p.  618. 


62  WEEDS  OF  FARM  LAND 

consolidation  1  of  the  soil.  Cereal  crops  are  very  little  harmed 
by  the  kainit  and  any  damage  is  merely  temporary,  but  peas, 
beans  and  other  leguminous  crops  are  more  liable  to  suffer,  as 
is  usually  the  case  when  chemical  weed  killers  are  used.  A 
comparison  of  the  various  tests  made  with  kainit  shows  that 
it  varies  in  its  effect  upon  weeds,  so  that  the  latter  may  be 
classified  according  to  their  degree  of  susceptibility  to  the 
dressing. 

(1)  Weeds   most    Susceptible   to    Kainit. — Charlock,    wild 
radish,  black  bindweed,  speedwell,  chickweed,  nettle,  groundsel, 
cornflower,  mayweed  (Anthemis  arvensis). 

(2)  Weeds  Moderately  Susceptible. — Persecaria,  spurry. 

(3)  Weeds  only  Slightly  Susceptible. — Sowthistle,  fumitory, 
poppy,  spreading  orache. 

Various  Manurial  Dressings. — Attempts  have  been  made 
to  reduce  weeds  by  attacking  before  germination  the  seeds  lying 
in  the  soil.  Any  substance  that  is  active  enough  to  destroy 
weed  seeds  would  be  equally  harmful  to  crop  seeds,  especially 
cereals,  so  if  this  method  is  adopted  it  must  be  tried  at  times 
when  no  crop  seeds  are  lying  in  the  soil,  and  when  a  sufficient 
period  will  elapse  before  sowing  to  permit  the  corrosive  effect 
of  the  dressing  to  pass  off.  Cornflower  seeds  in  the  soil  have 
been  successfully  destroyed  by  applications  of  carbolineum  or 
chloride  of  lime,  and  numerous  other  weed  seeds  disappeared 
at  the  same  time.2 

Spurry  is  chiefly  associated  with  light  soils  that  are  de- 
ficient in  lime,  and  sheep's  sorrel,  though  it  is  found  on  both 
light  and  heavy  soil,  also  indicates  lime  deficiency.  Liming 
has  been  tried  to  eradicate  both  these  weeds,  with  indifferent 
success  in  the  case  of  spurry,  with  rather  more  success  with 
sheep's  sorrel.  As  a  matter  of  fact  the  shortage  of  lime  is 
usually  very  marked  when  these  weeds  are  abundant,  and  it 
would  be  necessary  to  apply  an  almost  impossible  dressing  of 
lime  so  to  alter  the  balance  as  to  render  the  situation  untenable 
for  these  weeds.  A  mere  I  or  2  tons  of  ground  lime  per  acre 
has  no  effect  on  spurry,  though  doubtless  it  effects  some  de- 
gree of  improvement  in  the  soil  itself.  At  Hodsock,  an  ap- 
plication of  10  cwt.  salt  per  acre  on  very  light  sand  in  poor 
condition  killed  spurry  in  patches,  but  later  on  the  weed  took 
a  fresh  lease  of  life,  and  grew  even  more  luxuriantly  than  on 


1  Landw.  Jahrb.  (1914),  Bd.  XLVI,  pp.  627-657,  Summ.  in  Jour.  Bd.  Agric., 

»  P-  451. 

2Arb.  Deutsch.  Landw.  Gesell.  ;  see  Jour.  Ed.  Agric.  (1914),  XX,  pp.  909-910. 


XXI,  p.  451. 
rb. 


PREVENTION  AND  ERADICATION  OF  WEEDS       63 

an  untreated  plot,  flowering  and  fruiting  abundantly.     Possibly 
a  heavier  dressing  might  have  had  more  permanent  effect.1 

II.    Eradication  of  Weeds  from  Grass-land. 

On  arable  land  certain  periods  constantly  recur  when  the 
land  is  free  from  any  crop,  and  even  when  a  crop  is  growing 
there  are  spaces  of  bare  soil  between  the  plants  which  permit 
of  cultivation.  On  grass-land  all  is  different.  The  crop  is 
always  on  the  ground,  and  the  plants  are  so  closely  associated 
that  they  are  interlaced,  and  roots  and  shoots  alike  help  to 
form  a  mat  which  completely  covers  the  surface  of  the  ground. 
For  this  reason  weeds  on  grass-land  can  never  be  dealt  with 
without  taking  the  crop  into  full  consideration,  and  the  methods 
of  eradication  differ  considerably  from  those  adopted  on  arable 
land.  They  may,  however,  be  subdivided  into  the  same  two 
main  divisions  of  "mechanical  "  and  "chemical  "  means. 

(a)  Eradication  by  Methods  of  Cultivation — Mechanical 
Means. — When  grass-land  is  constantly  grazed  or  constantly 
cut  for  hay  the  herbage  takes  on  a  special  character  according 
to  the  method  of  treatment,  and  certain  weeds  find  congenial 
circumstances  under  each  set  of  conditions.  It  is  possible  to 
take  advantage  of  this  in  the  eradication  of  the  weeds,  as  by 
reversing  the  usual  order  and  haying  a  grazed  pasture,  or 
grazing  a  mown  field,  the  conditions  are  altered  and  the  weeds 
do  not  flourish  so  well.  Oxeye  daisy  (Chrysanthemum  leucan- 
themum)  grows  very  strongly  in  hay  fields  but  resents  inter- 
ference in  the  early  stages  of  growth.  Close  grazing 
with  sheep  in  the  early  spring  will  materially  reduce  it,  and 
for  the  same  reason  very  early  cutting  of  the  hay  crop  is 
effective.  This  method  can  also  be  used  to  reduce  false  brome 
(Brachypodium  sylvaticum  and  B.  pinnatum]  where  it  is  plenti- 
ful, as  on  down  pasture.  Care  is  needed  when  animals  are 
used  as  weed  eradicators,  as  if  the  grazing  is  carried  out  on 
the  wrong  lines  the  weeds  may  be  increased  rather  than 
diminished.  A  field  known  to  the  writer  at  Carhampton 
(Somerset)  was  infested  with  hardhead  (Centaurea  nigra}. 
When  the  land  was  grazed  exclusively  by  cows  the  hardheads 
waxed  more  and  more  strong,  the  cows  apparently  leaving 
them  severely  alone,  but  when  sheep  were  run  in  as  well 
an  improvement  was  soon  noticed,  as  the  plants  were  grazed 

1  "  Experiment  to  Check  the  Growth  of  Spurry,"  Jour.  Bd.  Agric.  (1901), 
VIII,  p.  54- 


64  WEEDS  OF  FARM  LAND 

down  closely  and  rapidly  exhausted.  On  the  other  hand, 
grazing  of  common  land  by  sheep  alone  may  encourage 
bracken,  because  if  broom  is  present  the  sheep  eat  the 
broom  down  closely  and  allow  the  bracken  to  flourish.  Cattle, 
however,  keep  the  bracken  under  and  allow  broom  to  hold  its' 
own.  On  dry  calcareous  pastures  where  the  herbage  is  short 
and  often  weed-infested,  geese  are  useful,  as  they  graze  very 
closely  and  appreciate  the  weeds.  Generally  speaking,  mixed 
grazing  is  advisable  where  destruction  of  weeds  is  the  aim, 
the  preferences  of  cattle  and  sheep  being  quite  different,  and  a 
more  effective  clearance  is  carried  out  when  both  agents  are  at 
work. 

If  hay  fields  are  infested  with  large  quantities  of  weeds 
that  seed  freely,  such  as  yellow  rattle  (Rhinanthus  crista-galli] 
early  cutting  of  the  hay  crop  is  often  useful  as  seeding  is 
thereby  prevented.  It  is,  however,  necessary  to  repeat  this 
for  two  or  three  years  in  succession,  for,  though  no  fresh  seeds 
may  be  produced,  there  are  large  stores  in  the  ground  which 
will  come  up  in  succeeding  years  and  provide  for  the  future  if 
they  are  not  cut  down.  Early  cutting  also  keeps  down  rank 
weeds  like  wild  chervil  (Anthriscus  sylvestris). 

The  most  usual,  and  probably  the  most  effective  way  of 
dealing  with  the  chief  weeds  of  grass-land,  such  as  nettle, 
thistle,  and  bracken,  is  judicious  cutting  at  appropriate  times. 
All  the  worst  pasture  weeds  have  underground  storehouses  of 
food,  either  stems  or  roots,  and  if  the  weeds  are  to  be  eradi- 
cated it  is  necessary  to  cut  when  those  storehouses  are  as 
empty  as  possible,  so  exhausting  the  plants.  Thistles  can  be 
cleared  by  cutting  three  times  in  the  season,  beginning  when 
the  plants  are  well  grown  but  have  not  come  into  flower.  If 
they  are  cut  in  the  first  week  in  June  and  then  twice  in  July 
for  a  couple  of  years  hardly  any  thistles  will  remain  by  the 
third  year.1 

If  three  cuttings  cannot  be  managed,  a  single  cutting 
about  the  middle  of  June  will  do  much  good.  Old  agri- 
culturists 2  recommend  that  thistles  should  be  mown  just 
before  they  blossom,  leaving  the  stems  about  4  inches  high, 
and  that  then  a  large,  heavy  wooden  roller  should  be  run  over 
the  field  so  as  to  bruise  the  stalks  thoroughly.  The  roller 
should  be  passed  over  four  times  one  way  and  twice  across. 

1  "  Destruction  of  Thistles"  (1908),  (1909).     Reports  of  Field  Experiments 
at  Harper  Adams  Agric.  College. 

2  Hunter,  A.  (1803),  "  Georgical  Essays,"  Vol.  Ill,  p.  203. 


PREVENTION  AND  ERADICATION  OF  WEEDS       65 

Yet  again  it  has  been  suggested  that  the  thistles  should  be  cut 
an  inch  above  ground,  as  water  then  gets  into  the  stub  and 
injures  the  crown  of  the  plant,  thus  enfeebling  the  shoots, 
whereas  if  the  plants  are  stubbed  off  below  ground  young  and 
luxurious  stools  shoot  up.1  Nettles  can  be  kept  under  by 
cutting  regularly  when  the  shoots  are  6  to  1 2  inches  high,  and 
ragwort  (Senecio  jacob&d)  can  be  eradicated  by  cutting  just  when 
it  begins  to  show  flower,  provided  it  is  not  too  strongly  estab- 
lished. It  sometimes  happens  that  a  weed,  uncommon  in  most 
places,  will  become  so  abundant  in  a  particular  district  as  to 
be  a  real  trouble.  This  is  the  case  with  the  wood  geranium 
(Geranium  sylvaticum}^  which  is  difficult  to  extirpate  if  it 
gets  a  hold.  Some  measure  of  success  has  been  obtained 
by  repeated  cutting  with  the  scythe,  and  it  is  possible  that 
pasturing  the  field  for  several  years  might  be  useful,  though 
cows  do  not  seem  to  eat  the  plant. 

Where  it  can  possibly  be  done,  bracken  is  readily  dealt 
with  by  means  of  cutting,  but  usually  it  covers  such  large 
areas  that  this  method  is  impracticable.  The  plants  should 
not  be  interfered  with  too  early  in  the  year,  one  or  two 
cuttings  made  when  the  bracken  is  well  grown  having  been 
found  to  exhaust  the  underground  food  stores  more  thoroughly 
than  if  the  young  fronds  are  prevented  from  developing. 
Early  July  and  August  seem  to  be  the  best  times  in  Wales 
and  Scotland,3  *  but  it  might  be  needful  to  make  the  first  cut 
rather  earlier  in  warmer  districts.  It  is  necessary  to  repeat 
the  process  for  two  or  more  years,  as  cutting  for  one  year 
only  is  of  little  use.  Another  way  is  to  run  chain  harrows 
repeatedly  over  the  ground  at  the  time  the  fronds  are  coming 
up,  for  if  this  is  done  thoroughly  and  persistently  the  plants 
are  greatly  weakened. 

Very  low,  close-growing  weeds,  like  the  stemless  thistle 
(Cirsium  acaule),  are  sometimes  very  troublesome  on  hilly 
pastures,  as  they  cover  a  considerable  amount  of  ground  with 
their  spreading  leaves  and  kill  out  all  other  vegetation  in  that 
area.  Their  habit  makes  them  difficult  to  eradicate,  and 
repeated  spudding,  carried  on  throughout  the  summer,  is 

1 "  Gleanings  from  Agriculture  "  (1802),  p.  409. 

2Milburn,  T.  (1916),  "Eradication  of  Crane's-bill  from  Meadows,"  Jour. 
Ed.  Agric.,  XXIII,  pp.  688-689. 

a  "  Eradication  of  Bracken,"  Dept.  Agric.,  Univ.  Coll.,  N.  Wales,  Bull.  V 
(1914);  Bull.  Ill  (1915). 

4  Gordon,  G.  P.  (1916),  "  Bracken  (Pteris  aquilina)  Life  History  and  Eradi- 
cation," Trans.  Highland  and  Agric.  Soc.,  Scotland,  XXVIII,  pp.  92-106. 

5 


66  WEEDS  OF  FARM  LAND 

practically  the  only  effective  remedy.  Small  patches  may  be 
cleared  by  covering  them  with  strong  sheets  of  tarred  paper, 
which  in  the  course  of  time  by  excluding  the  light  destroys 
all  vegetation  underneath.  Such  patches  must  be  re-seeded 
when  eradication  is  complete.1  The  same  method  may  be 
used  for  small  patches  of  nettles. 

Such  weeds  as  rushes,  willow-weed  (Polygonum  persecaria) 
and  marsh  horsetail  (Equisetum  palustre}  only  flourish  where 
there  is  a  plentiful  supply  of  water  held  up  by  the  soil,  so  that 
the  land  is  waterlogged.  Such  conditions  are  harmful  to  most 
of  the  plants  that  are  useful  in  herbage,  and  in  order  to  im- 
prove the  grass,  as  well  as  to  eradicate  the  weeds,  draining  is 
the  only  effective  remedy.  Marsh  thistle  (Cirsium  palustre} 
flourishes  in  damp  fields  and  is  also  found  on  hilly  pastures 
at  any  spot  where  a  spring  occurs,  but  it  rarely  causes  much 
trouble. 

In  nearly  every  case,  if  careful  attention  be  given  to  the 
matter,  it  is  possible  in  the  course  of  a  few  years  to  clear 
grass-land  of  weeds  by  the  above  methods  without  resorting  to 
more  drastic  measures.  Woodwax  (Genista  tinctorid),  how- 
ever, resists  every  attempt  to  eradicate  it,  and  when  once 
established  in  a  favourable  position  it  spreads  rapidly  and 
causes  great  depreciation  in  the  value,  of  the  pasture.  Stock 
refuse  to  touch  it,  either  green  or  in  hay,  and  apparently  the 
only  way  woodwax  can  be  eradicated  is  to  plough  up  the 
whole  field  and  keep  it  under  arable  cultivation  until  such 
time  as  the  land  is  cleared  of  the  underground  parts  of  the 
pest. 

On  rich  pasture  land  buttercups  grow  most  abundantly  and 
do  not  yield  to  ordinary  methods  of  eradication.  It  has  been 
found  that  a  clearance  can  be  made  by  ploughing  up  and  care- 
fully cleaning  the  land,  and  then  taking  at  least  one  root  crop 
off  it,  which  enables  still  more  cleaning  to  be  done.  If  the 
land  is  then  seeded  with  grasses  and  clover  of  good  quality  and 
is  treated  generously  a  good  pasture  soon  results,  which  may 
easily  provide  feed  within  one  year  from  sowing.2 

(b)  Eradication  by  Spraying  and  Manuring — Chemical 
Means. — On  grass-land,  as  on  arable  fields,  "  chemical  means  " 
resolve  themselves  into  treatment  by  liquid  sprays  and  the 
application  of  artificial  manures.  Here  again,  however,  the 

1  "  Cnicus  acaulis,"  Jour.  Bd.  Agric.  (1911),  XVII,  pp.  907-909. 
2Carruthers,   W.  (1906),  "Buttercups  in  Pastures,"  your,  Roy.  Ag.  Soc.. 
LXVII,  p.  258. 


PREVENTION  AND  ERADICATION  OF  WEEDS        67 

difference  in  the  requirements  of  the  crops  under  the  two 
methods  of  cultivation  is  so  great  that  the  eradication  of 
weeds  by  chemical  means  has  to  be  regarded  from  totally 
different  standpoints  in  the  two  cases. 

(i)  Sprays. — On  grass-land  sprays  have  only  a  limited 
degree  of  usefulness,  because  as  the  herbage  consists  of  a  mat 
of  plants  which  presents  in  the  aggregate  a  very  large  area  of 
leaf  surface,  the  amount  of  spray  that  is  necessary  to  kill 
certain  obnoxious  weeds  is  sufficient  to  find  a  lodgment  on  the 
leaves  of  the  herbage  and  work  havoc,  particularly  among  the 
broader  leaved  plants,  such  as  clover,  which  are  a  most  valu- 
able constituent  of  the  crop.  .  In  the  majority  of  cases  it  is  not 
possible  to  apply  the  spray  in  such  a  way  that  it  reaches  the 
weeds  without  affecting  the  herbage,  therefore,  generally  speak- 
ing, this  method  is  of  little  use  on  grass-land. 

Iron  sulphate  has  been  used  in  an  attempt  to  eradicate 
dandelions  from  lawns,  the  application  being  repeated  till  the 
treatment  had  to  be  discontinued  for  fear  of  injuring  the  grass. 
The  experiment  was  a  failure  on  account  of  the  great  vitality 
of  the  dandelion  roots,  which  remain  unhurt  even  though  the 
leaves  are  destroyed  by  the  spray.  Iron  sulphate  has  proved 
equally  ineffective  with  bracken,  and  copper  sulphate  is  of 
little  or  no  use  to  eradicate  thistles. 

Bracken,  on  account  of  its  tall  branching  habit,  is  more 
amenable  to  eradication  by  spraying  than  any  other  grass-land 
weed.  The  leafy  canopy  that  it  forms  offers  a  large  surface 
which  catches  and  retains  the  liquid  and  prevents  it  from  fall- 
ing to  the  ground  in  sufficient  quantity  to  injure  the  underlying 
herbage.  Sulphuric  acid  has  proved  effective  in  clearing  bracken 
from  areas  of  grazing  land.  A  few  hours  after  spraying  with 
a  5  per  cent,  solution  the  bracken  leaves  wilt,  and  a  few  days 
later  the  stems  turn  black  and  wither,  as  the  acid  is  gradually 
conducted  along  the  midrib  and  down  the  stalk,  eventually 
reaching  almost  to  the  underground  rhizome.  A  second 
spraying  after  a  new  crop  has  sprung  up  clears  off  the  bracken 
for  the  year  and  weakens  it  for  future  years.  The  grasses 
underneath  are  not  much  affected,  the  bracken  affording  them 
adequate  protection,  and  as  in  the  following  year  the  fern  is 
slower  in  making  its  appearance,  the  grasses  are  able  to  get 
ahead  earlier,  with  the  result  that  the  pasture  becomes  much 
improved.  Arsenite  of  soda  and  salt  have  also  been  used  with 
good  effect  on  bracken.  Arsenite  of  soda,  however,  is  inadvis- 
able as  a  general  rule,  because  it  is  so  very  poisonous  that  there 

5* 


68  WEEDS  OF  FARM  LAND 

is  danger  to  cattle  that  may  eat  the  herbage  or  hay  afterwards. 
The  Americans  apply  salt  solution,  using  200  Ib.  salt  per  acre, 
dissolved  at  the  rate  of  I  Ib.  salt  in  i-j-  quarts  of  water.  Two 
sprayings  a  year  are  necessary,  and  it  is  claimed  that  the 
method  is  effective.1  Salt  does  not  injure  the  herbage,  but 
on  the  contrary  exercises  a  beneficial  action  as  a  manure,  so 
that  the  salt  solution  is  free  from  the  objection  common  to  most 
sprays.  In  Germany  a  15  per  cent,  solution  of  kainit  has 
been  used  to  eradicate  nettles  in  springtime,  and  the  sugges- 
tion is  made  that  this  good  effect  may  be  due  to  the  presence 
of  salt  in  the  kainit. 

(2)  Manures. — The  principles  underlying  the  treatment  of 
grass-land  and  arable  land  by  manure  for  the  eradication  of 
weeds  are  essentially  different.  On  arable  land  the  application 
is  made  directly  to  the  weeds  with  a  view  to  burning  them  up 
and  so  destroying  them,  the  actual  beneficial  action  of  the 
manure  on  the  crops  being  a  somewhat  secondary  considera- 
tion. On  grass-land,  however,  it  is  impossible  so  to  differentiate 
between  weed  and  crop.  In  this  case  the  manures  are  applied 
with  the  view  to  encouraging  certain  desirable  species,  to 
enable  them  to  exercise  their  full  force  of  competition  and  so 
gradually  crowd  out  the  undesirable  plants. 

Apart  from  their  beneficial  influence  on  the  herbage,  salt 
and  lime,  perhaps,  exercise  a  more  direct  action  upon  certain 
weeds.  Nettles  are  less  likely  to  recur  if  infested  pastures 
are  treated 'with  6  cwts.  per  acre  of  salt  at  the  time  the  weeds 
are  cut  down  in  the  spring.  A  similar  dressing  in  early  April 
is  recommended  for  getting  rid  of  oxeye  daisy  (Chrysanthemum 
leucanthemum).  On  the  other  hand,  salt  does  not  seem  to 
injure  thistles  much,  as  the  effect  of  various  methods  of  cut- 
ting is  not  enhanced  by  an  after  application  of  salt.2 

Lime  in  one  of  its  various  forms  is  usually  most  effective 
in  reducing  the  quantity  of  sorrel  (Rumex  acetosd]  and  sheep's 
sorrel  (Rumex  acetosella\  though  it  is  still  doubtful  whether 
this  is  due  to  the  fact  that  the  sorrels  are  intolerant  of  the 
lime  itself  or  whether  they  are  merely  extremely  impatient  of 
the  increase  of  competition  due  to  the  improvement  of  the 
herbage  by  the  liming.  Be  that  as  it  may,  liming  may  be 
regarded  as  the  universal  remedy  for  these  weeds.  The 

1  Cox,  KL  R.  (1915),  "  Eradication  of  Ferns  from  Pasture  Lands  in  the 
Eastern  United  States,"  U.S.  Dept.  Agric.,  Farmer^  s  Bulletin,  No.  607,  p.  12. 

2"  Destruction  of  Thistles"  (1908),  Report  of  Field  Experiments  at  Harpe? 
Adams  Agric,  Coll, 


PREVENTION  AND  ERADICATION  OF  WEEDS       69 

quantities  used  vary  considerably,  the  nature  of  the  soil 
being  the  determining  factor  in  many  cases.  As  much  as 
5,  10,  or  15  tons  per  acre  have  been  applied  to  very  light 
soils,  deficient  in  lime,  but  the  difference  in  favour  of  the  very 
heavy  dressing  is  not  considerable.  A  more  general  applica- 
tion is  about  30  cwts.  per  acre  on  light  land,  ranging  up  to 
3  tons  per  acre  where  the  soil  is  heavy  and  wet.  Sheep's 
sorrel  will  also  yield  to  basic  slag  on  heavy  land,  prob- 
ably on  account  of  the  lime  in  the  slag.  If  docks  (Rumex 
crispus  and  R.  obtusifolius]  are  present  in  pastures  they  should 
be  spudded  out,  and  if  a  pinch  of  sulphate  of  ammonia  be 
placed  on  the  cut  ends  the  roots  are  almost  certain  to  be 
destroyed. 

False  brome  or  tor  grass  (Brachypodium  pinnatum  and 
B.  sylvaticunt)  is  sometimes  a  great  pest  on  down  pastures, 
where  its  coarse  growing  tufts  seriously  depreciate  the  grazing 
value  of  the  land.  Gas  lime  has  proved  an  effective  remedy 
when  about  2-J  cwts.  per  perch  (20  tons  per  acre)  are  applied 
in  as  fresh  a  state  as  possible  to  the  tufts  of  grass.1  If  spread 
in  autumn,  not  later  than  November,  the  false  brome  is  soon 
completely  killed  The  following  spring  the  land  needs, 
harrowing  and  working  up  to  a  fine  tilth,  when  a  mixture 
of  good  grass  seeds,  suitable  to  the  particular  soil,  must  be 
sown  to  provide  a  fresh  turf.  Gas  lime  is  most  powerful 
when  freshly  made,  and  loses  strength  rapidly  with  exposure, 
especially  during  rainy  weather. 

In  Cornish  experiments,  pasture  infested  with  moss  was 
cleaned  by  suitable  treatment  with  new  superphosphate  of 
28  to  30  per  cent,  strength.  A  single  application  of  6  cwts.  per 
acre  in  February  was  sufficient  where  only  a  little  moss  was 
present,  and  even  when  the  moss  was  of  long  standing,  forming 
a  dense  carpet  an  inch  thick,  a  second  dressing  was  completely 
effective.  It  is  recommended  that  the  superphosphate  be 
followed  with  a  similar  dressing  of  bone  meal  applied  the 
following  autumn,  in  order  to  encourage  the  growth  of  herbage 
and  discourage  a  fresh  invasion  of  moss.2  At  Wye,  on  chalky 
soil,  chemical  dressings  proved  of  little  use,  but  mechanical 

1  Hutchinson,  H.  P.  (1912),  "  Tor  Grass  or  False  Brome  and  its  Eradication 
from  Down  Pasture,"  Jour.  Bd.  Agric.,  XIX,  pp.  648-657. 

2  "  Destruction  of  Moss."      (a)   Cornwall  County  Council,  Memoranda  of 
Results    of  Agric.   Experiments,   1903    and    1904,     pp.   32-34.      (b)    Cornwall 
County  Council,  Notes   on  Agric.   and   Poultry   Experiments,   1905   and   1906, 
pp.  iq-2o. 


70  WEEDS  OF  FARM  LAND 

treatment  by  rolling,  harrowing,  and  the  treading  of  sheep 
was  more  efficacious  in  eradicating  moss.1 

(c)  Destruction  of  Weeds  by  Parasites. — Weeds,  in  common 
with  other  plants,  are  liable  to  attack  by  various  insect  and 
plant  enemies,  and  some  attempt  has  been  made  to  turn  this 
susceptibility  to  account  in  their  eradication.  Comparatively 
little  work  has  yet  been  done  in  this  direction,  but  definite 
experiments  have  been  made  in  New  Zealand  and  Italy  and 
probably  elsewhere.  Creeping  thistle  (Cirsium  arvense],  even 
in  this  country,  is  very  often  attacked  by  rust,  which  powders 
the  leaves  and  stems  with  dusty  brown  spots  and  greatly 
weakens  the  plants.  Cockayne 2  states  that  if  the  rust  is  to 
be  made  an  adequate  means  of  control  it  is  necessary  to  in- 
crease infection  considerably  beyond  that  occurring  naturally. 
It  is  possible  to  cultivate  the  spores  of  the  rust  on  thistle  leaves 
under  artificial  conditions.  These  rusted  leaves  are  crushed 
up  in  water  to  liberate  the  spores  and  the  liquid  is  sprayed  on 
to  the  thistles  in  their  early  stages  of  growth.  Under  these 
conditions  it  is  said  that  infection  is  virulent  and  the  disease 
spreads  rapidly. 

Italian  investigators  point  out  that  such  common  weeds  as 
thistle,  sowthistle,  bindweed,  poppy,  bladder  campion,  hawk- 
bit,  charlock,  willow-weed,  and  broomrape  are  under  natural 
conditions  frequently  attacked  by  parasites,  and  they  suggest 
that  with  due  encouragement  a  useful  means  of  weed  eradica- 
tion lies  at  hand.  Much  care  would  have  to  be  taken,  however, 
if  any  great  extension  of  this  method  were  attempted.  Many 
of  the  weed  parasites  may  be  capable  of  carrying  on  existence 
on  other  hosts,  and  crops  might  easily  be  attacked  by  the 
disease  employed  to  kill  the  weeds.  Also,  many  of  the 
fungus  diseases  of  plants  go  through  two  phases  of  existence 
on  two  utterly  different  hosts,  like  the  wheat  rust,  which  passes 
one  phase  on  wheat  and  the  other  on  such  plants  as  the  bar- 
berry. It  would  therefore  be  necessary  to  investigate  the  life 
history  carefully  in  every  case,  in  case  the  parasite  used  for  kill- 
ing the  weeds  should  be  one  that  spent  another  life  phase  on  a 
useful  crop.  This  danger  is  a  very  real  one,  and  some  workers 
suggest  that  it  would  be  more  advisable  to  encourage  insect 
pests  which  hinder  the  spread  of  weeds  by  riddling  the  seeds 

1  A.  D.  H.  (1900),  "  Moss  in  Pastures,"  South-Eastern  Agric.  Coll.  Journal, 
No.  g,  pp.  7*-72. 

2  Cockayne,  A.  H.  (1915),  "  Californian  Thistle  Rust  (Puccinia  suaveolens)," 
New  Zealand  Jour.  Agric.,  XI,  No.  4,  pp.  300-302. 


PREVENTION  AND  ERADICATION  OF  WEEDS       71 

and  so  destroying  their  power  of  germination.  The  seeds  of 
bindweed,  gorse,  and  some  species  of  wild  pea  are  often  so 
badly  attacked  that  it  is  difficult  to  find  an  uninjured  seed. 
At  best  this  method  would  be  of  limited  value,  some  of  the 
worst  weeds,  such  as  wild  oat  (Avena  fatua),  being  apparently 
immune  from  the  attacks  of  any  kind  of  parasite,  whether 
animal  or  fungus. 


CHAPTER  IV. 

VITALITY  OF  WEED  SEEDS. 

FROM  very  early  days  the  length  of  time  that  seeds  retain  their 
power  of  germinating  and  forming  new  plants  has  been  of  in- 
terest to  those  engaged  in  husbandry.  Even  Theophrastus 
(about  322  B.C.)  recorded  that  most  seeds  remained  alive  for 
more  than  three  years,  and  that  at  Patra,  in  Cappadonia,  seed 
was  said  to  remain  fertile  and  fit  for  sowing  for  forty  years. 
In  those  days  the  differences  in  the  behaviour  of  seeds  of  the 
same  species  in  this  respect  was  attributed  to  the  situation,  and 
seeds  in  elevated  places  exposed  to  plenty  of  wind  and  sun 
were  supposed  to  keep  longer  than  others.  Nowadays  the 
differences  are  attributed  more  to  the  conditions  of  storage  than 
to  anything  else,  and  it  is  realised  that  temperature,  moisture 
in  the  air  and  in  the  seed,  the  composition  of  the  surrounding 
atmosphere,  and  various  other  factors  all  play  their  part  in 
determining  how  long  a  seed  will  live. 

Popular  superstition,  fostered  by  the  reports  of  the  germina- 
tion of  "  mummy  "  wheat,  attributes  a  marvellous  longevity  to 
seeds.  Strict  inquiry  and  experiment,  however,  shows  that 
authentic  seeds  from  the  ancient  sepulchres  and  pyramids  will 
not  germinate,  the  seeds  obtained  from  such  situations  which  do 
grow  having  been  proved  to  be  frauds  inserted  by  the  Egyptian 
fellaheen  for  the  sake  of  gain.  In  all  other  cases  in  which 
very  old  seed  is  reported  to  have  germinated  doubt  has  been 
thrown  on  its  authenticity. 

With  a  view  to  ascertaining  the  approximate  time  that 
seeds  may  be  expected  to  live  under  conditions  of  dry  storage 
a  British  Association  Committee  l  carried  out  a  series  of  ex- 
periments with  over  200  very  varied  species  of  plants,  includ- 
ing a  number  of  common  wild  plants  and  farm  weeds.  The 
range  of  years  is  well  shown  by  the  following  table  : — 

1  Strickland,  H.  E.,  Daubeny,  Henslow,  and  Lindley  (1850,  1857),  "  Reports 
of  a  Committee  Appointed  to  continue  their  Experiments  on  the  Growth  and 
Vitality  of  Seeds,"  Rep.  Brit.  Ass.,  Adv.  Sci.,  No.  20,  pp.  160-168  ;  No.  27,  pp. 
43-56. 

72 


VITALITY  OF  WEED  SEEDS 


73 


Limit  of  Years  during  which 

Germinating  Capacity  was 

Retained. 

43 
42 
27 


26 

25 
21 

18 

15 
14 
13 

12 
10 

9 
8 
6 
5 
4 


Number  of  Species. 


i  (Leguminosae). 

i  (Leguminosae). 

7  (5  Leguminosae, 
i  Malvaceae, 
i  Tiliaceae). 

4 

4 

4 

i 

2 

I 

5 

2 

4 

2 
70 

3 

3 

9 

97 


It  is  thus  seen  that  the  majority  of  seeds  do  not  survive 
for  many  years  under  ordinary  conditions  of  storage,  and  that 
eight  and  three  years  seem  to  be  the  critical  periods  for  a 
large  number  of  plants.  The  actual  periods  of  survival  for 
the  wild  plants  and  farm  weeds  tested  in  these  experiments 
may  prove  interesting  : — 


Latin  Name. 
(i)     Ulex  europczus 

(i)     Convolvulus  major 


(I) 

(2) 

(3) 
(4) 
(5) 
(6) 
(7) 
(8) 
(9) 
(10) 


English  Name. 


Gorse 


cynapium 
Anagallis  arvensis 
Arctium  lappa 
Carum  carvi 
Daucus  carota 
Nepeta  cataria 
(Enanthe  crocata 
Rumex  obtusifolius 
Silene  inflata 
Vicia  sativa 


Greater  bindweed 

Fool's  parsley 

Scarlet  pimpernel 

Burdock 

Caraway 

Wild  carrot 

Catmint 

Hemlock  water-dropwort 

Broad-leaved  dock 

Bladder  campion 

Common  vetch    . 


Number 

of 
Years. 

15 


(1)  Conium  maiulatum 

(2)  Valerlanella  dentata 


Hemlock     . 

Narrow- fruited  corn  salad 


(1)  Bryonia  dioica 

(2)  Hypericum  hirsutum 

(3)  Plantago  media 

(4)  Tragopogon  porrifolius 

(5)  Valeriana  officinalis 

(6)  Verbasc^lnl  thapsus 


White  bryony     . 
Hairy  St.  John's  wort 
Hoary  plantain    . 
Purple  salsify 
Common  valerian 
Great  mullein 


74  WEEDS  OF  FARM  LAND 

As  the  above  tables  show,  the  seeds  of  some  leguminous 
plants  are  able  to  live  for  many  years  under  conditions  of  dry 
storage.  An  additional  proof  was  afforded  by  a  number  of 
seeds  obtained  from  the  Natural  History  Museum  through  the 
kindness  of  Dr.  Rendle,  the  keeper  of  the  Botanical  Depart- 
ment. These  were  tested  at  Rothamsted  in  1916,  and  one  seed 
of  black  medick  (Medicago  lupulind]  gathered  in  1884  grew 
well,  though  other  tested  seeds  of  similar  age  did  not  germin- 
ate. Many  weed  seeds  are  able  to  retain  their  vitality  under 
most  adverse  circumstances,  and  even  when  they  are  swallowed 
by  animals  or  birds  large  numbers  pass  through  the  alimentary 
tracts  unharmed.  This  has  been  definitely  proved  by  many 
experiments.  In  a  single  day  a  cow  was  estimated  to  have 
eaten  with  her  fodder  89,000  seeds  of  plantain  and  564,000 
seeds  of  chamomile.1  Of  these  85,000  and  198,000  respectively 
were  voided  in  the  dung,  apparently  uninjured,  and  the 
germinating  capacity  of  the  seeds  then  proved  to  be  58  per 
cent,  and  27  per  cent.  Dorph  Petersen  '2  fed  seeds  of  ribwort 
plantain  (Plantagolanceolatd]  and  mayweed  (Matricaria  inodord) 
to  a  cow,  and  found  that  after  passing  through  the  digestive 
system  of  the  animal  51  per  cent,  and  26  per  cent,  respectively 
germinated  out  of  the  total  number  of  seeds  fed.  About  50 
per  cent,  each  of  sheep's  sorrel  (Rumex  acetoselld)  and  fat  hen 
(Chenopodium  album)  passed  unharmed  through  a  pig,  and  I  5 
per  cent,  of  each  through  a  fowl,  although  the  majority  of 
seeds  are  usually  destroyed  in  the  latter  case  because  of  the 
grinding  action  in  the  gizzard.  In  another  case  in  America 
a  cow  and  a  horse  were  each  fed  with  2  Ib.  of  grain  screenings 
in  addition  to  their  other  food  each  night  and  morning  for 
seven  days.3  On  the  evening  of  the  seventh  day  they  were 
bedded  with  sawdust  and  the  excreta  for  that  night  collected. 
The  dung  and  sawdust  were  thoroughly  mixed  and  put  in 
boxes  in  a  greenhouse  and  four  weeks  later  the  following  seeds 
were  found  to  have  germinated  and  grown  : — 


1  Hansen,  K.  (1911),  "  Weeds  and  their  Vitality,"  Ugeskriftfor  Landmaend, 
56,  pp.  149-151.     See  Internat.  Re-view  of  Agric.,  1911,  p.  738. 

2  Dorph    Petersen    (1910),   Jahresbericht   der    Vereinigung  jur  angewandte 
Botanik.,  Summ.  in  your.  Bd.  Agric.,  XVIII,  igii,  pp.  599-600. 

.3  Patterson,  H.  J.,  and  White,  H.  J.  (1912),  "  By-Product  Feeds,"  Maryland 
Agric.  Expt>  Station  Bull.,  No.  168,  pp.  2-3. 


VITALITY  OF  WEED  SEEDS  75 

Cow's  Dung.  Horse's  Dung. 

149  Fat  hen  (Chenopodium  album)  1213  Fat  hen 

12  Pigweed  n  Pigweed 

14  Bindweed  (Convolvulus  arvensis)  12  Bindweed 

4  Foxtail  (Alopecurus  pratensis)  28  Foxtail 

2  Timothy  (Ph leum  pratense)  6  Timothy 

3  Clover,  Trifolium  sp. 
5  Mustard,  Brassica  sp. 

(morning  glory). 
2  Convolvulus  sp. 

It  thus  seems  that  more  weed  seeds  are  destroyed  by 
passing  through  the  digestive  system  of  a  cow  than  of  a  horse. 
Experiments  in  India  also  show  that  fat  hen  seeds  are  not 
injured  by  being  fed  to  bullocks,1  and  in  this  way  animals  do 
a  good  deal  towards  spreading  weeds  over  considerable  areas. 
Seeds  are  also  able  to  survive  after  being  eaten  by  birds,  as 
shown  by  various  authorities.2  3 

When,  however,  weed  seeds  are  buried  and  stored  up  in 
manure  heaps  many  of  them  succumb,  as  they  are  unable  to 
withstand  the  high  temperature  generated  in  a  well-made 
heap.  The  excessive  moisture,  together  with  the  acrid  nature 
of  the  liquid,  may  also  have  much  to  do  with  the  destruction 
of  the  weeds,  experiments  having  shown  that  certain  seeds, 
such  as  dodder,  lose  much  of  their  germinating  capacity  when 
they  are  immersed  in  liquid  manure  or  even  pure  water  for 
any  length  of  time.4  Even  if  they  are  only  slightly  buried 
beneath  the  surface,  the  majority  of  dodder  seeds  perish  in 
well-made  manure  in  about  a  month,  only  a  small  percentage 
retaining  their  vitality.  On  the  other  hand,  it  is  not  safe  to 
assume  that  all  weed  seeds  are  killed  by  storing  in  manure. 
Experimental  results  are  not  available,  but  it  is  exceedingly 
probable  that  many  seeds  escape,  as  many  of  them  are  pro- 
tected by  stout  outer  coats  which  enable  them  to  resist  the 
adverse  conditions.  The  seeds  of  fat  hen  (Chenopodium  album) 
not  only  survive,  but  germinate  and  flourish  exceedingly  on 
manure  heaps. 

To  the  farmer  and  gardener  the  most  important  aspect  of 

1  Milne,  D.  (1915),  "  The  Vitality  of  Seeds  Passed  by  Cattle,"  Agric.  Jour. 
India,  X,  pp.  353-369. 

2Collinge,  W.  E.  (1913),  "The  Destruction  and  Dispersal  of  Weed  Seeds  by 
Wild  Birds,"  Jour.  Bd.  Agric.,  XX,  pp.  15-26. 

3Kerner,  A.,  and  Oliver,  F.  W.  (1895),  "Natural  History  of  Plants,"  pp. 
863-865. 

4  Morettini,  A.  (1914),  Le  Stazioni  sperimentali  agrarie  italiane,  XLVII,  pp. 
733-751- 


7  6  WEEDS  OF  FARM  LAND 

the  vitality  of  seeds  is  their  power  of  surviving  for  prolonged 
periods  when  buried  in  the  soil.  It  is  beyond  question  that 
weed  seeds  will  lie  dormant  underground  for  several  years, 
starting  into  growth  whenever  favourable  conditions  occur, 
though  much  discrepancy  exists  in  the  estimates  of  the  time 
that  the  seeds  can  endure  burial  without  losing  their  power  of 
growth.  A  most  striking  instance  of  the  abundance  of  living 
weed  seeds  in  cultivated  soil  is  afforded  by  the  Somme  battle- 
field. A.  W.  Hill1  reports  that  in  July,  1917,  acres  of  poppies 
were  in  full  flower,  forming  a  stretch  of  flaming  scarlet  over 
wide  areas.  The  poppies  were  occasionally  replaced  by  a  few 
acres  of  white  chamomile  (Matricaria  chamomilld]  and  large 
patches  of  yellow  charlock  (Brassica  sinapis)  also  broke  the 
uniformity.  The  subsoil  of  the  area  is  chalk,  covered  with 
loam,  and  the  constant  shelling  has  churned  the  ground  up 
and  incorporated  the  soil  and  subsoil  very  thoroughly.  The 
charlock  was  specially  conspicuous  on  the  more  recently  dug 
graves  of  soldiers,  where  the  pure  chalk  had  been  brought  up 
to  the  surface.  On  the  sites  of  wrecked  woods,  sheets  of 
rose-bay  or  fireweed  (Epilobium  angustifoliuni]  were  conspicu- 
ous, and  round  the  edges  of  the  ponds  formed  by  shell  holes 
were  bands  of  toad  rush  (Juncus  bufonius  var.  gracilis),  ac- 
companied by  willow  weed  (Polygonum  persecaria],  the  latter 
often  growing  out  of  the  water.  In  addition  to  these  domin- 
ating plants,  a  large  variety  of  other  common  arable  weeds 
were  present  in  greater  or  less  amount.  It  was  obviously 
impossible  that  these  hordes  of  weed  seeds  could  have  been 
carried  by  any  known  means  of  transport,  whether  by  wind, 
animals,  birds,  vehicles,  or  human  beings,  and  the  inference  is 
that  they  were  all  present  in  the  soil  in  great  numbers  and 
seized  the  opportunity  to  germinate  provided  for  them  by  the 
unwonted  upheaval  of  the  soil. 

On  a  small  scale  a  similar  phenomenon  is  familiar  to  almost 
every  farmer.  It  is  a  matter  of  common  knowledge  that  if 
arable  land  is  turned  up  rather  more  deeply  than  usual,  or  if 
old  leys  are  ploughed  up,  in  the  following  season  large  quanti- 
ties of  weeds  will  appear  from  seeds  which  must  have  been 
buried  in  the  soil  awaiting  their  chance.  Belief  goes  further,  and 
it  is  often  said  that  large  crops  of  poppies,  charlock,  or  similar 
weeds  spring  up  even  when  "  old  pasture  "  is  ploughed.  In- 

1Hill,  A.  W.  (1917),  "The  Flora  of  the  Somme  Battlefield,"  Kew  Bull. 
Misc.  Information,  Nos.  9  and  10,  pp.  297-300. 


VITALITY  OF  WEED  SEEDS  77 

quiry  often  shows  that  this  old  pasture  has  been  under  arable 
cultivation  at  some  time  or  other,  thus  accounting  for  the 
presence  of  arable  weed  seeds.  Nevertheless,  there  are  many 
puzzling  cases  in  which  no  history  of  arable  cultivation  can  be 
traced.  Where  this  occurs  at  a  distance  from  other  arable 
fields,  as  sometimes  happens  when  moors  are  reclaimed,  it 
seems  that  of  necessity  the  seeds  must  be  carried  to  the  spot 
on  a  large  scale  by  some  means  of  transport  hitherto  undetected. 
As  a  general  rule,  however,  the  presence  of  seeds  buried  in 
the  soil  is  sufficient  to  account  for  the  large  weed  crops.  By 
experiment  and  observation  much  information  has  been 
gathered  as  to  the  ability  of  various  weed  seeds  to  withstand 
burial,  but  even  yet  our  knowledge  of  the  matter  is  very 
incomplete,  both  as  regards  the  species  concerned  and  the 
means  by  which  the  seeds  adapt  themselves  to  the  conditions 
of  burial. 

A  striking  characteristic  of  the  majority  of  farm  weeds  is 
the  abundance  of  seed  that  is  produced.  Only  a  very  small 
proportion  of  this  seed  finds  itself  immediately  under  conditions 
suitable  for  germination,  and  the  greater  number  of  seeds  are 
compelled  to  remain  dormant  or  else  to  perish.  These  wait- 
ing seeds  do  not  all  remain  on  the  surface  of  the  ground, 
large  numbers  being  carried  underground  by  various  agencies. 
Some  of  these  agencies  are  well  known,  but  others  are  easily 
overlooked.  The  various  means  of  burial  have  been  summed 
up  by  Woodruffe  Peacock  from  his  own  observation  as 
follows : — I 

(1)  Means  Influenced  by  the  Activity  of  Human  Beings  and 
Domestic  Animals. — Spade,  plough,  and  foot  pressure  by  stock. 
Cattle  drive  seeds  in  5  inches,  horses  3  inches,  sheep  2  inches 
or  more,  while  wheel  ruts  carry  seeds  down  10  inches  in  some 
cases. 

(2)  Environmental  Means. — 

(a)  Wind,  including  local  whirlwinds  and  storm  columns. 

(£)  Water,  which,  however,  usually  destroys  fertility. 

(/}  Mammals,  as  fox,  rabbit,  squirrel,  polecat,  Norway  rat, 

mole,  water  vole,  stoat,   weasel,  badger,  long-tailed 

field  mouse. 
09  Birds. 
(e]  Insects,  as  ants,  burrowing  insects,  larvae. 

1 1  am  indebted  to  the  Rev.  E.  A.  Woodruffe  Peacock  for  the  loan  of 
unpublished  MSS.  containing  this  information. 


78  WEEDS  OF  FARM  LAND 

(/)  Worms,  which  help  to  bury  seeds  4  or  5  feet,  especially 
smooth  or  rolling  seeds  like  those  of  charlock,  clovers, 
thistle  and  broom. 

(g)  Sun  and  earth  cracks,  in  which,  however,  most  seeds 
perish. 

(h)  Rock  cracks. 

Other  means  may  suggest  themselves,  but  the  above  list  is 
sufficiently  comprehensive  to  indicate  the  -great  variety  of 
ways  in  which  seeds  may  be  carried  underground  to  consider- 
able depths. 

When  once  burial  has  taken  place  the  conditions  determine 
whether  the  seeds  lie  dormant  or  start  into  premature  growth 
and  perish.  It  seems  probable  that  most  of  the  seeds  in  the 
top  few  inches  of  soil  are  in  the  presence  of  sufficient  water, 
air  and  warmth  to  enable  them  to  germinate,  and  it  then 
depends  upon  the  vigour  of  the  seedlings  and  the  relative 
depth  of  burial  whether  the  young  plant  can  reach  the  surface 
or  whether  it  perishes  ignominiously,  stifled  at  birth.  The 
deeper  buried  seeds,  however,  seem  to  be  able  to  set  up  some 
condition  of  equilibrium  with  their  surroundings,  and  instead 
of  germinating  many  of  them  lie  dormant,  awaiting  some  turn 
of  events  that  will  bring  them  into  more  favourable  circum- 
stances. Waldron  x  buried  seed  for  several  years  and  then 
tried  to  germinate  them,  and  found  that  the  deeper  buried 
seeds,  up  to  a  depth  of  10  inches,  were  the  better  preserved. 
As  years  go  on  numbers  of  the  buried  seeds  rot  and  perish 
in  other  ways,  but  a  certain  number  survive  for  long  periods 
of  time.  Very  definite  evidence  that  this  is  the  case  is  pro- 
vided by  the  crops  of  weeds  that  spring  up  when  methods  of 
cultivation  are  altered. 

An  instance  has  recently  occurred  in  Cumberland.  Forty 
acres  of  land  covered  with  gorse  and  heath  were  broken  up  in 
1893  and  kept  clean  under  arable  cultivation  for  over  ten 
years.  Between  1904-06  the  land  was  laid  down  to  grass, 
and  gorse  seedlings  soon  appeared.  These  were  stubbed  out 
without  being  allowed  to  seed  and  no  more  appeared  on  the 
pasture.  In  the  winter  1917-18  the  area  was  ploughed  up 
and  sown  with  oats,  and  gorse  seedlings  soon  reappeared. 
At  harvest  time  they  were  abundant  in  the  stubble,  being 
most  plentiful  where  the  gorse  was  originally  thickest.  These 

1  Waldron,  L.  R.  (1904),  "  Vitality  and  Growth  of  Buried  Weed  Seeds," 
North  Dakota  Agric.  Coll.  Bull.,  No.  62.  Also  see  Munerati,  O.,  and  Zapparoli, 
T.  V.  (1913),  Le  Stazioni  spenmentali  agrarie  italiane,  Vol.  XLVI,  pp.  347-371. 


VITALITY  OF  WEED  SEEDS  79 

seeds  had  been  buried  for  twenty-five  years,  and  still  retained 
their  power  of  germinating  as  soon  as  conditions  became  more 
favourable.1 

In  farming  practice  the  seeds  of  broomrape  (Orobanche  sp.) 
are  credited  with  the  power  of  lying  dormant  for  several  years 
and  germinating  in  succession.  This  has  been  corroborated  by 
pot  experiments  carried  out  for  a  period  of  fourteen  years, 
which  showed  that  broomrape  seeds  are  able  to  retain  their 
vitality  when  buried  in  soil  for  eight  years.2  Other  workers 
give  the  period  as  at  least  ten  years,  the  variation  being  prob- 
ably due  to  differing  conditions. 

From  the  practical  standpoint  the  case  is  very  clear  that 
many  weed  seeds  have  the  power  of  remaining  buried  for  a  long 
time  without  perishing,  but  in  the  absence  of  definite  experi- 
mental and  historical  evidence  many  fantastic  ideas  on  the 
subject  have  gained  credence.  With  a  view  to  obtaining  some 
definite  facts  a  series  of  experiments  have  been  carried  out 
with  soil  from  the  Rothamsted  fields,  of  which  the  detailed 
history  for  many  years  past  is  accurately  known.3  Old  arable 
fields  were  selected  which  had  been  grassed  over  for  fifty-eight, 
forty-three,  thirty-two,  and  ten  years,  while  Harpenden  Com- 
mon, Park  Grass  (a  piece  of  old  pasture  that  is  known  to  have 
been  under  grass  for  at  least  300  years),  and  also  a  field  that 
has  long  been  ploughed,  were  used  for  comparison.  Samples 
of  soil,  6  inches  square,  were  taken  inch  by  inch  to  a  depth  of 
12  inches,  the  utmost  care  being  used  to  avoid  contamination 
from  surrounding  soil.  These  samples  were  placed  in  shallow 
earthenware  pans  and  boxes  in  a  greenhouse,  kept  moist  and 
watched  for  about  two  years.  As  seedlings  appeared  they 
were  identified  and  removed  to  make  way  for  later  comers. 

As  was  to  be  expected  a  large  number  of  the  seedlings 
were  those  of  typical  grass-land  plants,  derived  from  seeds  from 
the  covering  herbage.  No  idea  could  be  formed  of  the  age  of 
these,  so  they  were  perforce  left  out  of  consideration.  The 
"  real  old  pasture  "  from  the  Common  and  Park  Grass  yielded 
all  told  six  seeds  of  typical  arable  weeds,  whose  presence  could 
readily  be  accounted  for  by  accidental  carriage  on  the  feet  of 
horses,  cattle,  human  beings,  wheels,  birds,  etc.  All  the  old 

1  Parkin,  J.  (1918),  "  Vitality  of  Gorse  Seed,"  Nature,  2552,  Vol.  102,  pp. 
65-66. 

2  Passerini,  N.  (1910),  "  Duration  of  Vitality  of  Seeds  of  Orobanche  crenata," 
Atti  R.  Accad.  Econ.  Agr.  Georg.  Firanze,  5,  ser.  7,  No.  i,  pp.  1-7. 

3Brenchley,  W.  E.  (1918),  "Buried  Weed  Seeds,"  Jour.  Agric.  Set.,  IX, 
pp.  1-31. 


8o 


WEEDS  OF  FARM  LAND 


arable  fields,  even  the  one  that  had  been  under  grass  for  fifty- 
eight  years,  yielded  arable  weeds  in  such  numbers  as  to  pre- 
clude the  possibility  of  accidental  infection  after  the  land  was 
grassed  over.  One  is  therefore  forced  to  the  conclusion  that 
the  seeds  had  lain  dormant  throughout  the  years. 

The  grand  total  of  typical  arable  weeds  obtained  from  the 
samples  are  given  in  the  following  table  : — 


Methods  of  Cultivation. 

Area. 

Years  under 
Grass. 

No.  of 
Samples. 

Total  Number 
of  Arable 
Weeds. 

Real  old  pasture 

Harpenden  Common 

? 

3 

2 

»>      »»         » 

Park  Grass 

p 

4 

4 

Old  arable  land 

Lab.  House  Meadow 

58 

4 

30 

>»         »         »»             • 

Barn  Field  Grass 

43 

4 

12 

»                 »»                 » 

Geescroft 

32 

4 

74 

»»                 »»                 >»                           * 

New  Zealand  I. 

10 

4 

457 

»»                 »>                 » 

New  Zealand  II. 

10 

4 

334 

Present  day  arable  land 

Long  Hoos 

o 

2 

782 

The  above  table  shows  that  after  ten  years  of  burial  very 
large  numbers  of  weed  seeds  are  still  alive  and  capable  of 
springing  into  activity  as  soon  as  circumstances  are  favourable. 
The  number  decreases  with  time,  but  even  after  thirty  years 
or  more  it  is  still  great,  as  74  seeds  from  an  area  I  foot 
square  by  I  foot  deep  implies  a  surprisingly  large  total  per 
acre.  Still  longer  periods  of  burial  fail  to  destroy  all  the 
seeds,  though  the  number  of  live  seeds  decreases  considerably. 
The  greater  number  of  the  arable  weed  seeds  were  found 
several  inches  below  the  surface,  and  many  of  them  were  rest- 
ing as  far  down  as  twelve  inches.  The  actual  number  found 
at  the  different  depths  are  shown  in  the  following  table  : — 

Total  Numbers  of  Arable  Weed  Seeds  from  Different  Depths, 


Period 

Area. 

under 
Grass. 

Depth  in  Inches. 

Total. 

Years. 

12       34       56789    10    ii    12 

Lab.  House 

Meadow  . 

58 

26659              II 

30 

Barn  Field  Grass 

43 

I                                   3341 

12 

Geescroft  . 

32 

12       35       9    14   12     89263 

74 

New  Zealand  I. 

10 

68  51     57   67     53   36   17   16   13   44     9   26 

457 

New  Zealand  II. 

IO 

57   46     51   36     48   30   14   16     7   16   13 

334 

Long  Hoos 

o 

60  92   162  97   115   82  63   40  21   29     8    13 

782 

VITALITY  OF  WEED  SEEDS 


81 


The  number  of  species  found  at  different  depths  is  also 
very  instructive.  As  might  be  expected,  in  present  day  arable 
land  and  land  that  has  been  grassed  over  for  comparatively 
short  periods  most  of  the  species  are  represented  in  the  top 
six  or  seven  inches,  a  less  number  occurring  at  lower  depths. 
When  the  land  has  been  under  grass  for  longer  periods,  how- 
ever, many  of  the  arable  species  tend  to  disappear  from  the 
upper  few  inches,  as  most  of  the  seeds  have  either  been  carried 
lower  or  have  started  into  growth  and  perished.  An  apparent 
exception  to  this  is  seen  in  the  Laboratory  House  Meadow, 
but  in  this  case,  as  the  meadow  is  close  to  the  house,  doubt  is 
thrown  on  the  age  of  some  of  the  buried  seeds  in  the  upper 
inches,  owing  to  the  proximity  of  allotments. 


Distribution  of  Species  of  Buried  Weed  Seeds. 


Number  of  Species  Occurring  at  Different  Depths. 

Area. 

of  Species 
Occurring. 

Depth  in  Inches. 

I 

2       3       4      5       6       7.      8    9  10  ii  12 

Lab.  House 

Meadow     .     . 

II 

2 

4435               I* 

Barn  Field  Grass 

4 

I                                         2         I                 I              I 

Geescroft  .     .     . 

9 

I 

11252323143 

New  Zealand    I 

14 

9 

9      9      9     ii       9       7      62321 

II 

13 

9 

ii     ip       9     10       9       4       3212 

Long  Hoos    .     . 

20 

10 

12     12     ii     10     13     ii     13     9     6     6     6 

The  number  of  species  of  weed  seeds  that  are  obtained  by 
this  method  after  burial  for  ten  years  and  more  is  somewhat 
limited.  After  the  shorter  periods  large  numbers  of  certain 
species  are  found,  especially  orache  (Atriplex  patula),  poppy, 
knotgrass  (Polygonum  aviculare],  field  speedwell  (Veronica 
tournefortii  and  V.  agrestis).  As  time  goes  on  the  poppies 
and  speedwell  drop  out  almost  entirely,  but  orache  and  knot- 
grass are  still  plentiful  even  after  many  years  of  burial. 

In  view  of  the  fact  that  large  crops  of  charlock  are  expected 
and  often  obtained  when  grassed-over  arable  land  is  ploughed 
up  it  is  interesting  to  notice  the  evidence  of  the  survival  of 
this  weed  in  this  experiment. 


WEEDS  OF  FARM  LAND 


Brassica  sp.      Charlock. 


Area. 


Lab.  House  Meadow 
Barn  Field  Grass  . 
Geescroft 
New  Zealand  I 

II    • 
Long  Hoos  . 


Period  under 
Grass. 
Years. 

58 
43 
32 
10 
10 
o 


Number  of 

Seedlings 

from  Samples. 

I 
3 

ii 
ii 

16 


The  number  of  seeds  was  not  great,  but  as  each  charlock 

plant  grows  large  and  is  very 
conspicuous,  it  is  probable  that 
quite  sufficient  would  be  present 
to  make  a  good  show  if  the  land 
were  again  ploughed.  As  a 
matter  of  fact,  New  Zealand 
was  broken  up  immediately  after 
the  samples  had  been  taken, 
and  the  following  season  an 
abundance  of  charlock  smothered 
the  field,  together  with  large 
quantities  of  ivy-leaved  and  field 
speedwell,  with  poppies  locally. 
The  great  decrease  in  the 
number  of  live  charlock  seeds 
as  the  period  of  burial  lengthened 
does  not  indicate  that  this  parti- 
cular seed  is  any  better  fitted  to 
survive  under  such  conditions 
than  many  other  species  that 
are  less  striking  in  appearance. 
The  Rothamsted  records  in 
several  cases  give  details  of  the 
weeds  that  occurred  on  the 
fields  sampled  when  they  were  originally  under  the  plough, 
and  a  comparison  of  these  with  the  seedlings  obtained  in  the 
pans  shows  a  close  resemblance,  thus  further  strengthening 
the  theory  that  the  weeds  in  the  pans  had  sprung  up  from 
seeds  that  had  remained  alive  though  buried  for  years.  The 
occurrence  of  seedlings  of  creeping  thistle  (Cirsium  arvense)  is 
of  interest,  as  fanners  often  maintain  that  the  seeds  of  this 
plant  are  abortive  and  never  germinate  (Fig.  25). 

The  reasons  why  seeds  buried  in  soil  should  retain  their 


FIG.  25. — SEEDLING  OF  CREEPING 
THISTLE  (Cirsium  arvense)  which 
came  up  from  Seed  Buried  in  Soil 
from  New  Zealand  Field  at  Roth- 
amsted. 


VITALITY  OF  WEED  SEEDS  83 

power  of  germination  longer  than  those  kept  in  dry  storage  or 
those  on  the  surface  of  the  soil  are  still  rather  obscure.  The 
question  is  complicated  and  probably  depends  upon  a  certain 
balance  being  reached  between  the  various  physiological  con- 
ditions in  which  the  seed  finds  itself.  The  temperature  is 
more  equable  some  inches  below  the  surface  of  the  soil,  and 
while  seeds  near  or  on  the  surface  may  perish  from  cold  during 
the  winter,  buried  seeds  do  not  usually  suffer  from  extreme  cold. 
Strong  sunlight  may  also  be  very  injurious  to  germination,  and 
this  again  is  ruled  out1  The  stage  of  maturity  is  another 
important  factor.  Immature  seeds  soon  perish,  but  mature 
and  properly  ripened  seeds  contain  just  enough  water  to 
enable  them  to  lie  dormant,  and  the  conditions  of  air  and 
moisture  surrounding  them  in  the  soil  seem  to  be  such  as  to 
enable  them  to  mark  time  without  undergoing  further  desicca- 
tion or  other  vital  changes.  When  once  the  long  buried  seeds 
are  brought  to  the  surface  they  are  likely  to  start  into  growth 
very  quickly.  Experiments  have  shown  that  many  species  of 
seeds  that  have  been  kept  in  unfavourable  circumstances 
germinate  rapidly  when  the  conditions  are  improved,2  for  in- 
stance, when  they  are  brought  from  prolonged  darkness  into 
light.  On  the  whole,  the  more  deeply  buried  seeds  retain 
their  germinating  capacity  the  best,  as  was  clearly  shown  by 
the  Rothamsted  experiment  above  described  and  also  by  pot 
experiments  carried  out  by  Dorph  Petersen  with  various  seeds 
buried  3,  6,  and  12  inches  below  the  surface. 

Much  more  information  and  evidence  are  needed  before  it 
will  be  possible  to  explain  fully  why  large  crops  of  certain 
weeds,  as  charlock,  poppies,  and  fireweed,  spring  up  when  land 
is  ploughed  or  cleared  even  when  the  weeds  were  not  present 
before  the  change  of  conditions.  It  is,  however,  quite  clear 
that  in  the  majority  of  cases  sufficient  live  weed  seeds  are 
buried  in  the  soil  to  supply  far  larger  crops  of  weeds  than  any 
farmer  need  desire. 

i 

1Giimbel,  H.  (1912),  Untersuchungen  iiber  die  Keimungverhaltnisse  ver- 
schiedener  Unkrauter,  Landivirtsch.  Jahrb.,  XLIII,  pp.  215-331. 

2  Praktische  Blatter  fur  Pflanzenbau  und  -schutz  (1912),  Summ.  in  Jour.  Bd. 
Agric.,  XIX,  pp.  231-232. 


•       CHAPTER  V. 

HABITS  OF  WEEDS. 

THE  habits  of  growth  and  the  length  of  time  that  weeds  live 
have  much  to  do  with  the  methods  adopted  in  dealing  with 
them,  and  also  with  the  amount  of  damage  that  they  are  able 
to  inflict  upon  crops.  A  knowledge  of  the  way  in  which  a 
particular  weed  grows  is  often  a  valuable  asset  to  the  farmer, 
enabling  him  to  eradicate  it  in  the  most  effective  way,  and  in 
some  cases  an  understanding  of  the  life  history  of  a  plant 
reveals  some  weak  point  in  development  at  which  it  may  most 
readily  be  attacked  with  every  hope  of  success.. 

Duration  of  Weeds. — Weeds  may  be  divided  into  three 
classes  according  to  the  length  of  time  they  live : — 

(i)  Annual  Weeds. — These  are  plants  in  which  the  whole 
cycle  of  existence  is  completed  within  twelve  months.  After 
germination  the  vegetative  growth  is  rapid,  so  that  the  plant 
is  in  flower  within  a  comparatively  short  space  of  time. 
The  ripening  of  the  fruits  is  equally  rapid,  and  the  pro- 
duction of  seed  is  thus  ensured.  Annual  weeds  depend 
entirely  upon  seed  for  their  reproduction,  and  the  whole 
energies  of  the  plants  are  directed  towards  the  formation  of 
this  essential.  As  a  general  rule  the  quantity  of  seed  produced 
is  very  abundant,  so  that  even  though  much  of  it  may  be  lost 
by  decay  or  other  means  a  sufficiency  is  left  to  carry  on  the 
species.  If  the  season  be  hot  and  dry,  and  there  is  danger  that 
plant  life  will  suffer  from  drought,  the  annual  weeds  hurry  into 
flower  at  an  early  stage  of  development  in  order  that  they 
may  not  die  before  their  seeds  are  formed.  It  is  no  uncommon 
sight  in  a  dry  summer  to  see  the  most  miserable  specimens 
putting  up  a  weak  flower  and  then  ripening  miniature  seed 
pods.  The  same  effect  is  produced  by  other  adverse  circum- 
stances, such  as  the  presence  of  poisonous  substances  in  the 
soil.  Unless  they  are  killed  outright,  annuals  strive  to  the 
very  utmost  to  produce  some  stock  of  seed  before  they  give 

84 


HABITS  OF  WEEDS  85 

up  the  struggle  for  existence.  This  habit  of  life  makes  it  quite 
easy  to  eradicate  annual  weeds  by  careful  cultivation.  If  the 
seeds  are  allowed  to  germinate  and  the  young  plants  are  cut 
down  before  they  flower,  seed  formation  is  prevented  and  the 
plants  have  no  other  means  of  reproducing  themselves.  It  is 
necessary  to  keep  a  careful  watch  because  some  plants,  such 
as  ivy-leaved  speedwell,  chickweed,  shepherd's  purse,  pimpernel 
and  others  begin  to  flower  very  early  in  life,  and  these  early 
flowers  ripen  and  shed  their  seeds  long  before  the  latest 
formed  buds  have  opened.  Many  of  the  arable  weeds  are 
annual  in  duration,  some  of  the  most  common  being  groundsel, 
spurry,  poppy,  chickweed,  speedwells,  pimpernel,  charlock, 
radish,  thyme-leaved  sandwort,  fat  hen,  spurge,  fumitory,  and 
cleavers,  but  the  commoner  weeds  of  grass-land  usually  live 
longer,  as  the  short-lived  plants  find  it  difficult  to  establish 
their  transitory  existence  under  the  conditions  found  in  pasture 
or  meadow  land. 

(2)  Biennial  Weeds. — These  are  plants  which  spread  their 
life  cycle  over  two  years.  In  the  first  season  the  seed 
germinates  and  vegetative  growth  is  active,  but  flowers  are 
not  produced.  In  many  cases  large  quantities  of  reserve  food 
substances  are  laid  up  during  this  time  and  stored  away  in  the 
roots  or  underground  stems  for  use  during  the  following  year. 
In  the  second  year  the  energies  of  the  plant  are  directed  to 
seed  formation,  the  reserves  of  food  being  used  up  for  the 
purpose  of  developing  the  flower  and  fruits.  When  this  is 
safely  carried  out  the  plant  dies  exhausted. 

If  a  biennial  plant  starts  growing  early  in  its  first  year,  and 
the  summer  is  hot  and  dry,  it  often  happens  that  flower  forma- 
tion is  hastened.  Under  these  circumstances,  instead  of  wait- 
ing till  the  second  year,  the  flowering  spikes  are  thrown  up 
and  seed  is  produced  at  the  end  of  the  first  season,  so  that 
the  weed  becomes  an  annual  for  the  occasion.  The  object  of 
this  change  of  habit  is,  once  again,  to  ensure  seed  formation, 
for  the  biennials  are  as  dependent  as  are  the  annuals  on  seed 
for  the  propagation  of  their  kind,  not  being  provided  with 
means  of  vegetative  reproduction. 

Very  few  weeds  are  truly  biennial  in  habit,  as  they  labour 
under  such  serious  disadvantages.  The  cultivation  of  the 
soil  during  the  growing  season  prevents  the  plants  from  mak- 
ing much  growth  and  from  storing  up  food  to  tide  them  over 
the  winter.  Even  if  they  do  escape  for  the  time,  it  is  more 
than  probable  that  spring  cultivation  will  cut  them  up  before 


86  WEEDS  OF  FARM  LAND 

they  have  any  opportunity  of  flowering  and  seeding.  As  they 
have  no  other  means  of  propagation  it  is  obvious  that  biennials 
have  a  very  poor  chance  under  these  circumstances  except  in 
the  isolated  cases  in  which  for  any  reason  a  change  to  an 
annual  habit  is  made.  Consequently  few  or  no  biennials  are 
to  be  found  among  arable  weeds,  and  even  those  of  grass-land 
are  few  in  number,  the  most  noteworthy  being  wild  carrot, 
spear  thistle  and  marsh  thistle,  the  hemlock  from  the  border 
of  the  fields  being  similar  in  type. 

(3)  Perennial  Weeds. — These  are  plants  which  have  no 
definite  term  of  existence,  but  which,  when  once  established, 
and  if  left  to  their  own  devices,  live  on  from  year  to  year, 
constantly  spreading  and  increasing  in  quantity.  All  of  them 
can  and  do  arise  from  seeds,  but  they  are  by  no  means  depen- 
dent on  this  method  for  their  perpetuation.  Perennials  have 
various  arrangements  for  vegetative  reproduction  whereby  new 
plants  can  arise  from  different  portions  of  the  original  parent 
without  the  intervention  of  seed.  They  also  form  thickened 
and  creeping  underground  stems,  bulbs,  or  strong  bulky  roots,  in 
which  quantities  of  food  are  stored  up  for  the  use  of  the  plant 
when  necessary.  Most  of  the  perennial  farm  weeds  die  down 
to  the  surface  of  the  ground  in  the  winter  but  live  on  in  their 
buried  parts,  and  then,  in  the  spring,  the  stored  up  food  is 
utilised  to  give  the  plant  a  fresh  start  and  to  carry  it  on  until 
the  new  aerial  stem  and  leaves  are  able  to  take  up  the  work 
of  nutrition.  Fuller  details  of  the  habit  of  the  perennials  will 
be  found  under  the  next  heading  "  Habits  of  Growth  of  Weeds," 
especially  in  sections  3,  5,  6,  8,  9. 

Habits  of  Growth  of  Weeds. — Farm  weeds  vary  much  in 
their  habits,  so  that  for  every  condition  of  life  weeds  are 
found  to  suit  the  particular  circumstances.  Broadly  speak- 
ing, annual  plants  adopt  one  set  of  habits  and  perennials 
another,  but  this  is  not  an  absolutely  hard  and  fast  rule.  It 
is  not  always  possible  to  be  quite  certain  how  to  classify  some 
weeds,  as  their  mode  of  growth  may  combine  the  characteristics 
of  two  classes,  and  the  following  grouping  must  only  be 
regarded  as  a  broad  and  general  division,  which  is  liable  to  be 
modified  by  different  observers  or  by  the  same  observer  at 
different  times  and  places. 

(i)  Erect  Weeds. — Under  this  heading  may  be  classed  all 
those  weeds  which  throw  up  an  erect  stem,  more  or  less 
branched,  bearing  leaves,  flowers  and  fruit.  Nearly  all  weeds 


HABITS  OF  WEEDS  87 

of  this  type  are  annuals  and  develop  either  a  tap  root  or  a 
more  fibrous  root  which  does  not  thicken  up  to  any  great  ex- 
tent, e.g.  charlock,  spurge,  fat  hen,  wild  radish,  nipplewort, 
corn  marigold,  corn  cockle,  groundsel,  shepherd's  needle, 
poppy,  red  dead  nettle,  corn  buttercup,  and  others. 

In  a  few  perennial  plants,  as  pignut  and  bulbous  buttercup, 
the  same  erect  habit  of  growth  is  adopted,  but  the  base  of  the 
stem  is  considerably  swollen  and  serves  as  a  storehouse  of 
food  from  year  to  year.  Some  of  the  erect  weeds  make  big 
plants  and  have  large  leaves,  and  as  they  grow  up  with  the 
crop  rob  it  of  a  good  deal  of  light  as  well  as  taking  up  food 
and  water  from  the  soil. 

(2)  Tufted   Weeds. — These  grow  close  to  the  ground  and 
often  branch  considerably,  forming  a  close  tuft  of  leaves  and 
stems   that   is   very  characteristic   in   appearance.      Most  are 
annual   in   duration  :     lady's    mantle,    mouse-ear    chickweed, 
swine  cress   and  annual   meadow  grass  are  the  most  familiar 
examples.    In  some  situations  the  three  former  have  a  tendency 
to  send  out  longer  branches,  so  that  this  group  merges  into 
the  next.      Spurry,  annual  knawel,  mayweed,  and  chamomile 
also  grow  near  the  ground  and  branch  repeatedly,  and  may 
be  included  in  this  section. 

(3)  Weeds  with   Stems   Trailing  over  the  Surface  of  the 
Ground,  but  not  Rooting   at  the  Nodes. — Some  of   the  most 
troublesome  annual  weeds  come  into  this  section,  and  given 
favourable  circumstances  a  single  plant  is  able  to  cover  a  large 
area  of  ground      Each  weed  possesses  a  single  main  root,  and 
sends  out  horizontal  branches  which  again  branch  repeatedly 
until  at  length  a  dense  mat  is  formed  which  effectually  covers 
the  surface  of  the  soil  and  prevents  the  ingress  of  light  and  air. 
A  single  plant  of  orache  seen  in  the  summer  of  1918  at  Hel- 
mingham  in  Suffolk  measured  over  4  feet  in  diameter,  and  it 
needs  little  imagination  to  realise  that  no  other  vegetation, 
whether  weed  or  crop,  had  any  opportunity  of  flowering  within 
the  area  covered   by  this  plant     The  trailing  weeds  are  very 
troublesome  among  roots,  as  they  tend  to  cluster  round  the 
young  plants  and  are  not  removed  by  hoeing,  so  that  unless 
they  are  carefully  taken  out  by  handweeding  the  crop  has 
little  chance,  for  root  crops  are  very  impatient  of  overcrowding, 
particularly    in    the    earlier    stages.       Knotgrass,  -chickweed, 
speedwells  of  various  species,  orache,  pimpernel,  and  wild  pansy 
are  plentiful    on  arable  land,  and    several    kinds    of  trailing 
geraniums  occur  as   \veeds  on  leys,   where  they  are  harmful 


88  WEEDS  OF  FARM  LAND 

because  they  make  the  grass  patchy  by  choking  it  out  where- 
ever  they  grow. 

(4)  Rosette  Weeds. — The  characteristic  feature  of  these 
weeds  is  that  no  leafy  stem  is  produced,  but  a  number  of  leaves 
arise  together  from  a  rootstock  or  much  compressed  stem 
lying  just  below  the  ground  level.  In  some  cases,  as  in  the 
daisy,  dandelion,  and  plantain,  the  naked  flowering  stems  arise 
in  the  same  way,  but  in  others,  as  in  shepherd's  purse  and  the 
various  docks,  a  leafy  flowering  shoot  is  thrown  up.  Two  types 
of  rosettes  may  be  distinguished,  but  the  habitat  often  deter- 
mines which  type  will  be  produced  by  a  particular  species  of 
weed. 

(a)  Rosettes  in  which  the  leaves  have  little  or  no  leafstalk 
and  the  blades  are  pressed  close  to  the  ground,  as  in  daisy, 
shepherd's  purse,  hoary  plantain,  and  sometimes  the  greater 
plantain. 

(U)  Rosettes  in  which  the  leaves  may  or  may  not  have 
leaf-stalks,  but  in  which  the  blades  are  somewhat  raised  from 
the  ground,  forming  a  cluster  rather  than  a  true  rosette,  as  in 
dandelion,  docks,  ribwort  plantain,  and  greater  plantain  (usual 
form). 

The  first  type  of  rosette  causes  much  trouble  in  grass-land, 
because  all  vegetation  is  choked  out  from  underneath  the  weeds, 
and  as  the  latter  often  occur  in  large  numbers  and  continually 
spread,  infested  pastures  rapidly  deteriorate  in  quality  unless 
measures  are  taken  to  check  the  invaders. 

Most  of  this  group  are  perennial,  shepherd's  purse  being 
almost  the  only  common  annual  weed  that  adopts  this  habit. 

(5)  Weeds  Creeping  on  Surface  of  Ground  and  Rooting  at 
Nodes. — These  weeds  closely  resemble  the  trailers  (3),  but  are 
distinguished  by  the  abundant  supply  of  adventitious  roots 
that  are  developed  from  the  leaf-joints.      Most  of  them,  how- 
ever, are  perennials,  as  the  extra  rooting  system  provides  for 
a  continual  stock  of  young  plants  which  are  able  to  establish 
themselves  and  survive  the  winter.     Creeping  buttercup,  silver- 
weed,  and  bent  grass  are  representative  of  these  weeds,  but  the 
habit  is  less  common  than  most  of  the  others. 

(6)  Weeds  Creeping  by  Rhizomes  or  Underground  Stems  and 
Sending  up  Green  Shoots  above  Ground. — This  habit  is  confined 
to  perennial  weeds,  and  the  group  includes  some  of  the  very 
worst  of  the  farm  weeds.     The  rhizomes  may  either  creep  near 
the  surface  as  in  couch-grass,  stinging  nettle,  corn  mint,  and 
rush,  or  they  may  descend  to  various  depths,  running  vertically 


HABITS  OF  WEEDS  89 

or  horizontally  as  circumstances  dictate,  as  in  thistle,  horse- 
tail, and  coltsfoot.  In  either  case  buds  are  formed  which  push 
up  above  the  soil  and  develop  into  green  shoots,  producing 
leaves  and  flowers.  The  food  stored  underground  during  the 
winter  is  used  to  start  the  buds  into  activity  in  the  spring,  and 
later  on  the  green  shoots  form  an  extra  stock  of  food  and 
pass  it  down  below  to  be  stored  for  the  next  winter,  thus 
completing  the  vicious  circle.  Dormant  buds  are  plentiful  on 
the  rhizomes,  and  if  a  small  piece  of  the  latter  is  broken  off 
the  buds  develop,  roots  and  shoots  are  sent  out,  and  a  new 
plant  results.  The  rhizomes  enable  the  weeds  to  migrate  con- 
siderable distances,  and  when  great  efforts  have  been  made  to 
clear  a  particular  spot  it  is  no  unusual  occurrence  to  find  the 
pest  turning  up  many  yards  away,  perhaps  in  another  field,  to 
which  it  has  travelled  and  escaped  notice. 

Coltsfoot  is  slightly  different  in  habit  from  the  other  weeds 
in  this  class.  Early  in  the  spring,  about  February,  clusters  of 
flower  buds  are  pushed  above  ground,  which  give  rise  to  the 
familiar  yellow  flowers,  somewhat  resembling  small  dandelions. 
No  leaves  are  produced  at  this  time,  but  when  flowering  is 
nearly  or  quite  over  more  buds  develop  from  other  parts 
of  the  rhizomes,  and  this  second  set  produces  the  large 
cottony  leaves  that  often  carpet  the  ground  where  coltsfoot  is 
abundant  This  separation  of  flower  and  leaf  leads  many 
people  into  the  mistake  of  thinking  that  they  are  not  connected, 
and  too  often  the  flowers  are  allowed  to  ripen  seed  with  im- 
punity by  the  very  farmers  who  make  determined  onslaughts 
on  the  plant  when  the  leaves  have  appeared. 

(7)  Climbing  and  Scrambling  Weeds. — A  few  plants  pro- 
duce very  long,  weak  stems,  which  raise  themselves  into  the 
light  and  air  by  twining  or  scrambling  round  other  vegetation. 
When  these  weeds  are  plentiful  among  crops  they  are  most 
troublesome,  because  they  tend  to  strangle  the  crop  plants  and 
prevent  the  latter  developing  properly,  and  also,  if  the  stems 
of  cereals  are  weak,  the  climbing  weeds  pull  them  down  and 
cause  them  to  "  lodge  "  without  any  opportunity  of  rising  again. 
The  worst  climbing  weeds  in  this  class  are  convolvulus  (or 
bindweed)  and  black  bindweed.  The  former  is  a  perennial, 
with  long  twisted  rhizomes  from  which  an  abundance  of  weak 
aerial  stems  are  given  off,  while  the  latter  is  an  annual  whose 
leaves  bear  such  a  similarity  to  those  of  the  true  bindweed  that 
the  two  weeds  are  often  confused.  Both  are  very  leafy,  and 
when  they  occur  abundantly  in  corn  crops  it  is  necessary  to 


90  WEEDS  OF  FARM  LAND 

dry  the  sheaves  most  thoroughly  as  the  bindweeds  are  apt  to 
cause  heating  in  the  stack. 

Vetches  occasionally  appear  as  farm  weeds,  though  most  of 
them  are  typically  hedge  plants.  They  are  climbers  in  which 
the  end  leaflet  of  the  compound  leaf  is  modified  into  a  tendril. 
This  is  irritable  and  curls  round  any  available  support,  enabling 
the  weak  stemmed  plant  to  drag  itself  up. 

Goosegrass  (Galium  aparine]  does  not  climb,  but  scrambles 
over  and  among  the  crops,  clinging  to  them  by  the  minute 
hooked  prickles  with  which  every  part  of  the  plant  is  clothed. 
The  slender  stems  may  reach  a  length  of  several  feet,  and 
their  clinging  habit  causes  considerable  interference  with  farm 
operations.  Goosegrass  is  only  an  annual,  but  under  suitable 
conditions  it  grows  very  rapidly,  forming  large  numbers  of 
prickly  fruits  which  are  very  easily  picked  up  and  carried 
about  by  anything  with  which  they  come  into  contact 

(8)  Weeds   with  Swollen  Internodes. — This  habit,  fortun- 
ately, is  unusual  among  farm  weeds.      In  the  knotty  or  onion 
couch  the  portions  of  stem  between  the  successive  leaves  are 
swollen  up  into  large  knobs,   several    occurring   in  a  string. 
These  are  perennial,  very  tenacious  of  life,  and  resistant  to 
most  attempts  to  eradicate  them.     Every  "  knot  "  will  produce 
a  new  plant,  so  that  if  the  weed  is  broken  by  ploughing  it  is 
encouraged  to  increase.     If,  again,  the  clusters  of  knots  are 
brought  to  the  surface  in  cultivation  and  are  allowed  to  dry, 
they  separate  into  the  individual  knots,  and  additional  plants 
result.     It  is  therefore  specially  important  that  this  weed  should 
be    cultivated   out    with   as  little  breakage   as   possible,    and 
should  be  promptly  removed  from  the  soil  before  it  dies  and 
breaks  up. 

(9)  Bulbs. — The  weeds  that  belong  to  the  Lily  family  are 
characterised    by  bulbs,  which    are    underground   clusters   of 
swollen  scale  leaves  springing    from  a  small   flattened  stem. 
Buds  arise  between  these  scale  leaves  and  develop  into  new 
bulbs,   and   seeds   are   also  produced,   so  that  such  weeds  as 
meadow    saffron   (Colchicum  autumnale]  and  Bath  asparagus 
(Ornithogalum  pyrenaicum)  have  two  certain  methods  of  re- 
production.    Wild  onion  possesses  a  third  method,  as  small 
bulbils  arise  among  the  flowers,  which  fall  to  the  earth  and 
develop  into  fresh  plants. 

(10)  Parasitic   Weeds. — These  are  few  in  number,  but  are 
capable  of  working  much  havoc  when  they  are  present  among 
crops.    Their  habit  is  to  attach  themselves,  by  means  of  suckers, 


HABITS  OF  WEEDS  91 

to  some  part  of  a  selected  host  plant  and  steadily  rob  their 
victim  of  food.  A  bad  attack  of  dodder  may  utterly  ruin  a 
clover  crop  by  the  constant  sapping  of  strength  consequent  on 
the  loss  of  nutritive  substances.  Yellow  rattle,  broomrape, 
and  bartsia  are  the  other  most  familiar  parasites,  but  they  are 
all  sufficiently  important  to  demand  more  extended  notice. 
(See  Chapter  VI.) 


CHAPTER  VI. 

PARASITIC  WEEDS. 

ORDINARY  green  plants  use  the  soil  and  the  atmosphere  as 
storehouses  from  which  they  draw  the  raw  materials  of  their 
food,  these  being  then  converted  by  the  vital  processes  of  the 
plants  into  substances  which  can  be  utilised  to  build  up  the 
tissues.  The  roots,  by  means  of  fine  root  hairs,  take  up  from 
the  soil  water  in  which  nitrogen  (in  the  form  of  nitrates),  and 
compounds  of  such  mineral  substances  as  potassium,  phos- 
phorus, iron,  calcium,  magnesium,  etc.,  are  dissolved.  This 
dissolved  raw  food  passes  up  through  the  woody  part  of  the 
plant  into  the  leaves,  where  it  meets  with  supplies  of  carbon 
which  are  taken  in  from  the  air  in  the  form  of  carbon-dioxide. 
During  the  daytime  complicated  chemical  changes  take  place 
resulting  ultimately  in  the  formation  of  such  substances  as 
sugar  and  starch,  which  are  then  conveyed  to  the  various  parts 
of  the  plant  where  they  are  needed.  This  preparation  of  food 
can  only  go  on  in  green  parts  in  the  presence  of  light,  so  that 
plants  that  do  not  possess  green  colouring  matter  or  in  which 
leaves  are  absent  and  are  not  replaced  by  green  stems  are  not 
able  to  prepare  their  own  food,  but  must  obtain  it  ready  for 
use  from  some  other  source.  Some  plants  of  this  nature 
attach  themselves  in  various  ways  to  other  living  plants  and 
steal  their  food  all  ready  prepared,  thus  earning  the  name  of 
parasitic  plants. 

Parasitic  plants  may  be  divided  into  two  classes : — 

(1)  Total  parasites,  in   which   green   colouring   matter   is 
entirely  absent,  and  which  cannot  prepare  any  food  for  them- 
selves, so  that  they  are  absolutely  dependent  upon  other  plants 
for  their  food. 

(2)  Partial  parasites,  which  possess  a  certain  amount   of 
green  colouring  matter  which  is  often  very  poor  in  quality  ; 
they  are  able  to  prepare  part  of  their  food,  but  are  dependent 
upon  other  plants  for  most  of  their  nutriment 

Total  parasites  are   capable  of  doing  great  harm  to  the 

92 


PARASITIC  WEEDS 


93 


host  plants  on  which  they  live,  as  they  drain  the  hosts  of  so 
much  food  that  the  latter  are  necessarily  much  enfeebled. 
Partial  parasites  usually  do  less  harm,  because  their  demands 
are  not  so  heavy,  but  they  can  do  much  injury  if  they  attack 
weakly  hosts. 

Among  farm  weeds  there  are  a  few  species  that  live 
parasitically,  some  of  which 
are  of  real  economic  impor- 
tance, while  the  rest  are  more 
interesting  than  dangerous. 
Both  total  and  partial  para- 
sites are  represented,  dodder 
(Cuscuta  spp.)  and  broomrape 
(Orobanche  spp.*)  being  the 
chief  total  parasites,  and 
yellow  rattle  (Rhinanthus 
crista-galli]  and  red  bartsia 
(Bartsia  odontites)  the  most 
common  partial  parasites.  In 
addition  to  these,  eye-bright 
(Euphrasia  spp.\  cow-wheat 
(Melampyrum  spp.)  and  red 
rattle  (Pedicularis  spp.)  are 
sometimes  found  in  grass- 
land and  are  probably  parti- 
ally parasitic  on  the  roots  of 
grasses,  but  they  are  not 
known  to  do  much  damage. 

DODDER  (Cuscuta  spp.\ 
(Fig.  26),  Nat.  Order  Con- 
volvulacece. — Dodder  is  fre- 
quently seen  amongst  clover 
and  gorse,  appearing  as  long, 
slender  red  threads  which 
interlace  the  stems  and 
branches.  The  threads  are 
not  rooted  in  the  ground  and  they  bear  no  leaves,  but  are 
studded  in  the  summer  with  clusters  of  small  white  flowers 
which  are  followed  by  four-seeded  capsules  or  seed  vessels. 
Several  species  of  dodder  are  scattered  over  the  world,  each 
species  having  one  or  more  host  plants  on  which  it  usually 
lives.  Among  others  the  clover  dodder  (Cuscuta  trifolii) 
patronises  clover  and  other  leguminous  plants ;  flax  dodder 


FIG.  26. — DODDER  (Cuscuta  trifolii), 
parasitic  on  Clover. 


94  WEEDS  OF  FARM  LAND 

(C.  epilinum)  seems  to  live  entirely  on  flax  ;  lesser  dodder  (C. 
epithymuni)  on  the  roots  of  heath,  thyme,  and  other  small 
shrubby  plants,  while  the  common  or  greater  dodder  (C. 
europced)  is  much  less  exclusive  and  is  found  on  a  great 
variety  of  plants  in  Europe  and  parts  of  Asia. 

The  seeds  of  dodder  fall  to  the  ground  or  are  sown  along 
with  a  crop.  They  start  into  growth,  each  seedling  develops 
a  small  root  and  sends  up  a  thin  delicate  stem  into  the  air. 
This  stem  twists  round  seeking  for  a  congenial  host,  but  if 
this  is  not  found  the  seedling  dies.  If  a  host  is  available  the 
dodder  twists  round  it  and  rapidly  fastens  itself  on  to  the  stem 
by  means  of  suckers  ;  when  connection  is  established  the 
roots  and  the  lower  part  of  the  stem  of  the  dodder  die  away, 
leaving  the  parasite  disconnected  from  the  ground  and  entirely 
dependent  upon  the  host  for  its  food. 

The  suckers  are  small  swellings  or  tubercles  resembling  the 
beginnings  of  roots.  They  gradually  bore  their  way  through 
the  epidermis  or  outer  skin  of  the  host  plant,  then  through  the 
underlying  soft  tissue  or  cortex  until  they  reach  the  central 
part  of  the  stem.  Intimate  connection  is  thus  established 
between  the  conducting  strands  of  the  host  plant  and  those 
of  the  dodder,  so  that  a  clear  passage  is  available  for  the 
transference  of  food  in  a  ready  prepared  condition  from  the 
host  to  the  parasite.  If  much  dodder  is  present  the  drain  on 
the  resources  of  the  host  is  often  so  severe  that  the  victim 
cannot  stand  the  strain  but  dies  of  starvation,  and  in  this  way 
large  areas  of  clover  are  often  ruined.  Dodder  is  recognised 
as  one  of  the  most  dangerous  foes  of  this  crop,  and  therefore 
legislation  is  adopted  against  it,  making  it  an  offence  to  sell 
crop  seed  contaminated  with  dodder  seed. 

Although  most  species  of  dodder  are  usually  associated 
with  one  or  more  well-defined  host  plants,  it  is  now  found  that 
some  of  them  are  capable  of  infecting  other  plants,  including 
various  kinds  of  weeds.  This  renders  the  pest  still  more 
dangerous,  for  dodder,  being  under  favourable  circumstances, 
is  often  able  to  pass  safely  through  the  winter  in  the  vegetative 
condition  and  may  succeed  in  escaping  observation  on  the  other 
hosts  even  when  the  main  crop  has  been  drastically  dealt  with. 
The  clover  dodder  (Cuscuta  trifolit)  has  been  known  to  spread 
on  to  hoary  plantain  and  bedstraw,  the  common  dodder  will 
spread  from  nettles  to  grasses,1  and  another  species  (Ctiscuta 

1  Montemartini,  L.  (1913),  Alcune  malattie  nuove  o  rare,  Rivista  di 
Patologia  vegetale,  VI,  pp.  204-210. 


PARASITIC  WEEDS  95 

arvensts)  is  found  en  a  variety  ef  weeds  as  well  as  *n  clAver, 
including  deck,  deg's  mercury  (Mercurialis  perennis),  s€>w- 
thistle,  charlock,  black  nightshade  (Solanum  nigruni),  nettle, 
creeping  thistle,  wild  lettuce,  knetgrass,  and  mayweed.1 

Didder  seeds  retain  their  pewer  «f  germination  for  several 
years,  even  when  buried  in  the  soil.  The  germination  €>f  the 
seeds  is  spread  ever  a  l«ng  period,  the  largest  percentage 
earning  up  during  the  first  menth  after  sewing,  while  the 
ethers  appear  later  en  in  gradually  decreasing  numbers. 
Seme  e-f  the  seeds  are  "  hard  "  and  it  is  these  which  form  a 
dangere-us  stock  in  the  sail  for  several  years  after  infection. 
Although  dedder  seeds  will  lie  dormant  in  the  seil  for  se  leng, 
Italian  investigators  claim  that  they  are  net  able  te  withstand 
the  action  ef  farmyard  manure.  If  they  are  buried  in  a  heap 
»f  manure  mest  ef  the  seeds  lese  their  p«wer  ef  germinating 
within  abeut  a  menth,  only  a  very  small  percentage  retaining 
their  vitality  ever  ledger  perieds.  It  is  censidered,  therefore, 
that  there  is  comparatively  little  danger  ef  spreading  dodder 
infection  by  means  ef  farmyard  manure,  provided  the  latter  is 
well  made  and  properly  treated. 

Eradication  of  Dodder. — In  this  country  clover  dodder  (C. 
trifolii)  is  the  species  that  causes  most  trouble.  As  prevention 
is  better  than  cure  every  effort  should  be  made  to  sow  seed 
that  is  absolutely  free  from  dodder  seeds.  With  the  excep- 
tion of  an  American  species  (C.  gronovii],  which  has  extra 
large  seeds  resembling  in  size  those  of  clover,  the  ma- 
jority of  dodder  seeds  can  be  effectively  removed  from  clover 
and  lucerne  by  screening  with  sieves  of  suitable  mesh.  A 
large  proportion,  but  not  all,  of  the  dodder  seeds  may  also  be 
destroyed  by  dry  heating,  as  they  lose  their  power  of  germina- 
tion at  temperatures  that  are  harmless  to  the  associated  clover 
seeds.  The  most  effective  temperatures  seem  to  be  : — 2 

149°  F.  for  2  hours. 

158°  F.  for  30  minutes  or  for  I  hour. 

167°  F.  for  30  minutes  or  for  I  hour. 

If  infection  does  occur  and  the  patches  are  observed  before 
they  have  spread  too  far,  the  affected  part  of  the  crop  should 
be  dug  up,  covered  with  chaff,  sprinkled  with  paraffin  and 
burnt  on  the  spot.  The  dodder  should  not  be  torn  out  with 
a  rake,  as  this  serves  to  spread  the  trouble.  If  infected  plants 

1  D'Ippolito,  G.   (1913),  Le  Stazioni  sperimentali   agrarie  italiane,   XLVI, 
pp.  540-549. 

2  Ibid. 


96  WEEDS  OF  FARM  LAND 

are  noticed  during  the  winter  they  should  be  cut  off  an  inch 
or  two  below  the  surface  of  the  soil  with  a  sharp  spade  or 
hoe,  and  burnt  on  the  spot.  If  this  is  impossible  the  plants 
should  be  carried  away  with  the  greatest  care,  in  order  to 
prevent  seeds  or  pieces  of  dodder  being  scattered  about  the 
field. 

If  the  infection  is  too  widely  spread  to  be  dealt  with 
locally,  it  is  best  to  plough  under  the  affected  crop,  burying 
the  dodder,  provided  seed  formation  has  not  begun.  If  seeds 
are  forming  the  crops  should  be  cut  as  low  down  as  possible 
and  burnt.  As  the  clover  dodder  is  usually  associated  with 
leguminous  plants  only,  it  is  advisable  to  avoid  growing  such 
crops  for  a  period  of  years,  in  order  that  the  dodder  seeds 
lying  dormant  in  the  soil  may  have  an  opportunity  to  germinate 
and  die  for  lack  of  a  suitable  host  from  which  they  can  obtain 
their  nourishment.  During  this  period  the  land  should  be 
cropped  with  cereals,  grasses,  or  roots,  which  the  clover  dodder 
does  not  attack.1 

In  some  cases  spraying  is  said  to  be  an  effective  means  of 
eradicating  dodder.  It  is  reported  that  a  1 5  per  cent,  solution 
of  sulphate  of  iron  kills  the  parasite  and  also  blackens  the 
clover  badly,  but  that  the  latter  recovers  and  sprouts  again. 
Arsenite  of  soda,  at  the  rate  of  ^  Ib.  in  5  gallons  of  water  has 
proved  successful  on  lucerne.2  French  experiments 3  also 
show  that  heavy  dressings  of  sodium  nitrate  (8  cwts.  per  acre) 
will  destroy  dodder  and  at  the  same  time  strengthen  the 
alfalfa  or  other  leguminous  host,  thus  enabling  the  latter  to 
resist  the  drain  of  the  parasite  to  a  greater  degree.  Sodium 
nitrate  is  advantageous  in  that  it  does  not  exercise  the 
same  dangerous  burning  action  on  vegetation  as  sulphate  of 
iron. 

BROOMRAPE  (Orobanche  spp.},  (Figs.  27,  28),  Nat.  Order 
Orobanchacece. — The  lesser  broomrape  (Orobanche  minor]  is 
the  species  of  most  economic  importance  in  this  country  as  it 
fastens  on  the  roots  of  clover,  lucerne,  sainfoin,  and  other 
leguminous  crops  and  sometimes  does  considerable  damage, 
completely  ruining  the  second  cut  of  clover  in  some  cases. 
It  also  attacks  a  number  of  other  plants  which  are  not 

1  (1906),  "  Dodder,"  Jour,  Bd.  Agric.,  XIII,  pp.  331-338. 

2  (1908),  "Eradication  of  Dodder,"  your.  Bd.  Agric.,  XV,  pp.  280-281. 

3  Farcy,  J.  (1910),  Journal  d1  Agriculture  pratique,  No.  42,  pp.  497-498. 


FIG.  27. — BROOMRAPE  (Orobanche  minor),  parasitic  on  Sainfoin. 
Right. — Sainfoin  plant  not  attacked. 

Left. — Sainfoin  plant  attacked  by  Broomrape,  showing  the  harmful  effect  on 
growth. 


FIG.  28. — BROOMRAPE  (Orobanche  minor),  parasitic  on  Lucerne. 


PARASITIC  WEEDS  9? 

leguminous.1  Another  British  species,  branched  broomrape 
(O.  ramosa),  is  of  more  importance  in  other  countries,  for 
instance  in  America,  where  it  works  havoc  among  hemp  crops 
and  also  attacks  tomatoes. 

The  parasite  appears  above  ground  as  a  thick  fleshy  stem 
bearing  a  number  of  flowers  which  rapidly  form  seed  vessels 
containing  an  abundance  of  very  small  seeds,  which  are 
scattered  by  the  wind.  The  whole  plant  is  dingy,  usually 
brown  or  purple  in  colour,  with  no  leaves  and  no  trace  of 
green  colouring  matter. 

Broomrape  seeds  can  lie  dormant  in  the  soil  for  at  least 
ten  years,  probably  longer.  They  are  apparently  unable  to 
germinate  unless  they  are  in  the  immediate  neighbourhood  of 
the  fine  fibrous  roots  of  their  proper  host,  and  their  power  of 
lying  dormant  enables  them  to  await  suitable  conditions  with- 
out suffering  from  the  delay.  Generally  speaking,  they  attack 
well-developed  host  plants,  as  if  they  attacked  young  and 
weakly  plants  the  hosts  would  be  so  debilitated  by  the  drain 
on  their  resources  that  the  parasite  would  fail  to  obtain 
sufficient  food  to  make  satisfactory  growth. 

The  broomrape  seed  germinates  and  puts  out  a  small 
radicle  or  root  which  penetrates  a  fine  rootlet  of  the  host  and 
soon  connects  itself  with  the  conducting  strand.  This  radicle 
at  once  begins  to  steal  food  from  the  host,  and  stores  it  up  in 
the  form  of  a  starchy  reserve  food  in  the  upper  part  of  the 
radicle  which  swells  up  and  gradually  forms  a  nodule  on  the 
host  root.  This  nodule  increases  in  size  and  after  a  time  a 
number  of  small  prominences  appear  on  its  surface,  a  larger 
swelling  developing  just  where  the  seed  coat  was  at  first 
present.  The  small  prominences  grow  out  into  roots  which 
surround  the  nodule  closely  and  attack  the  host  roots  in  other 
places,  thus  providing  several  points  of  attachment  instead  of 
only  one.  The  larger  swelling  develops  into  a  shoot,  short 
and  covered  with  scales,  which  eventually  elongates  and  grows 

1  Garman,  H.  (1903),  Kentucky  Agric.  Exp.  Stat.  Bull.,  105,  p.  31,  gives 
a  list  of  English  plants  attacked  by  Orobanche  minor. 

Crepis  virens  Poterium  sanguisorba  ? 

Crithmum  maritimum  Trifolium  arvense. 

Daucus  carota  pratense. 


Digitalis  pur  pur  ea 
Hypocharis  radicata 
Lotus  corniculatus 
Medicago  lupulina 
sativa 


rep  ens. 
strictum. 
subterraneum. 
striatum. 
filiforme. 


7 


98  WEEDS  OF  FARM  LAND 

up  above  the  soil  to  bear  the  flowers.  The  greater  part  of  the 
life  of  the  broomrape  is  passed  below  ground,  as  the  nodule 
spends  twelve  months  or  more  in  developing  into  a  fair  sized 
bulb-like  structure,  before  pushing  aerial  shoots.  After  the 
first  crop  of  clover  or  lucerne  has  been  cut  a  good  deal  of 
food  is  stored  up  below  ground,  and  as  the  soil  is  well  warmed 
up  at  the  time,  the  broomrape  on  the  root  thrives  on  the  extra 
food  and  warmth,  develops  very  rapidly,  and  throws  up 
flowering  stems  which  ripen  their  fruits  and  seeds  within  a  very 
short  space  of  time. 

Eradication  of  Broomrape. — The  best  remedy  is  prevention, 
by  sowing  clean  seed.  The  broomrape  seeds  are  some  of  the 
very  smallest  seeds  that  occur,  so  it  is  an  easy  matter  to  screen 
them  out  from  the  large  seeds  of  the  crops.  If  unfortunately 
infection  does  occur,  the  broomrapes  should  be  pulled  up  by 
hand  immediately  they  appear  above  the  soil,  before  they  have 
time  to  form  seed,  and  should  then  be  burnt.  The  attachment 
with  the  host  roots  is  not  very  firm,  and  the  whole  parasite 
easily  comes  away.  This  procedure  must  be  carried  out 
systematically  for  several  years  until  the  dormant  seeds  have 
all  developed.  It  is  useless  to  do  it  for  one  or  two  years 
only,  as  a  very  few  plants,  if  neglected,  are  sufficient  to  re-seed 
a  large  area.  The  clover  or  other  crop  should  be  encouraged 
by  judicious  manuring  and  liming,  to  make  it  strong  enough 
to  withstand  the  attacks  of  the  parasite,  and  when  the  crop  is 
eventually  ploughed  up  no  other  leguminous  plant  should  be 
sown  on  the  same  ground  for  several  years.  The  interval 
should  be  as  long  as  possible,  a  case  being  on  record  l  in  which 
broomrape  attacked  clover  after  seven  years  had  elapsed  since 
the  last  clover  crop,  the  new  attack  being  so  severe  that  the 
whole  crop  had  to  be  ploughed  up. 

Broomrape  deserves  more  attention  than  it  usually  gets, 
for  many  farmers  fail  to  realise  the  life  history  of  the  plant  and 
do  not  connect  the  poorness  of  their  second  cut  of  clover  with 
the  armies  of  dingy  brown  spikes  that  spring  up  on  their 
fields. 

YELLOW  RATTLE  (Rhinanthus  crista-galli.\  Nat.  Order 
Scrophulariacece. — This  is  only  a  partial  parasite,  as  it  possesses 
yellowish-green  leaves  which  are  able  to  help  in  the  nutrition 
of  the  plant,  though  much  of  the  food  is  stolen  from  a  host. 
Two  species  are  really  included  under  the  one  name. 

(i)  Rhinanthus  minor. — Small  yellow  rattle,  which  is  very 

1 "  Broomrape  "  (1908),  Jour.  Bd.  Agric.,  XV,  pp.  176-180. 


PARASITIC  WEEDS  99 

common  in  pasture  land  and  is  parasitic  on  the  roots  of 
grasses  and  possibly  on  some  other  species  also. 

(2)  Rhfnanthus  major  (Fig.  29). — Greater  yellow  rattle, 
which  occasionally  makes  its  appearance  in  cornfields,  where 
it  attacks  the  cereal  crops  and  does  much  mischief. 

The  small  yellow  rattle  is  not  usually  taken  much  notice 
of  by  farmers,  but  it  reduces  the  crop  and  turns  black  in  dry- 
ing, rendering  hay  in  which  it  is  abundant  distasteful  to 
animals.  The  greater  yellow  rattle  is  local  in  this  country — 
the  writer  has  only  seen  it  in  part  of  Wiltshire,1 — but  if  it 
gets  a  good  footing  it  is  capable  of  depreciating  or  even 
ruining  the  cereal  crops. 

Unlike  dodder  and  broomrape  the  yellow  rattle  develops 
like  a  normal  plant  with  an  underground  branching  root 
system  and  an  aerial  stem  bearing  leaves  and  flowers.  Its 
roots  range  themselves  alongside  the  fibrous  roots  of  the 
host,  and  at  the  point  of  contact  suckers  are  sent  out 
which  penetrate  to  the  conducting  strands  of  the  host  root 
and  absorb  nitrogenous  food  material  therefrom  (Fig.  30). 
The  attachment  is  very  intimate,  and  it  is  impossible  to 
separate  host  and  parasite  without  breaking  the  roots  badly. 
Occasionally  the  suckers  appear  to  penetrate  the  base  of  the 
stem,  and  in  one  instance  a  row  of  suckers  was  seen  along  the 
outside  of  the  husk  of  a  barley  grain.  The  plant  is  able  to 
manufacture  its  own  carbohydrate  food  (as  starch  and  sugar) 
with  the  aid  of  its  green  leaves  and  the  carbon-dioxide  taken 
in  from  the  air.  Large  quantities  of  winged  seeds  are  produced 
which  can  retain  their  vitality  in  the  soil  for  some  years,  thus 
securing  the  propagation  of  the  plant 

Eradication. — On  grass-land  yellow  rattle  is  most  abundant 
in  fields  that  are  regularly  cut  for  hay,  as  when  once  it  has 
gained  a  footing  it  has  yearly  opportunities  of  ripening  quan- 
tities of  seed.  It  is  less  often  seen  on  grazing  land,  and  can 
be  eradicated  or  at  least  greatly  reduced  if  constantly  mown 
land  is  grazed  for  a  number  of  years,  especially  if  sheep  are 
used.  If  hay  must  be  taken  it  should  be  cut  early  so  as  to 
forestall  the  ripening  of  the  yellow  rattle  seeds.  The  grazing 
is  more  effective  if  it  is  supplemented  by  a  dressing  of  basic 
slag,  7  cwts.  per  acre,  applied  before  the  end  of  November. 
In  some  cases  it  is  useful  to  apply  about  5  to  7  cwts.  per  acre 
of  salt  early  in  the  year,  as  soon  as  possible  after  the  seedlings 

1  Brenchley,  W.  E.  (1913),  "Yellow  Rattle  as  a  Weed  on  Arable  Land," 
Jour.  Bd.  Agric.,  XIX,  pp.  1005-1009. 

7* 


100 


WEEDS  OF  FARM  LAND 


Fjo.  29. — YELLOW  RATTLE  (Rhinanthus  major),  parasitic  on  Oats. 


PARASITIC  WEEDS 


101 


-  D 


FIG.  30. — SECTION  ACROSS  BARLEY  ROOT  PENETRATED  BY  A  SUCKER  OF 
YELLOW  RATTLE  (Rhinanthus  major). 

A.  Root  of  Barley. 

B.  Sucker  of  Yellow  Rattle. 

C.  Cells  through  which  the  stolen   food  passes  from  the  Barley  into  the 
Yellow  Rattle. 

D.  Root  of  Yellow  Rattle. 


102  WEEDS  OF  FARM  LAND 

of  the  parasite  appear,  as  by  this  means  large  numbers  of  the 
latter  are  killed.  The  seedlings  may  also  be  destroyed  by 
harrowing  in  March  or  even  later,  but  this  is  not  usually  as 
effective  as  dressing  with  salt.1 

Eradication  on  arable  land  is  a  matter  of  greater  difficulty. 
In  ordinary  rotation  courses  cereal  crops  follow  one  another 
at  intervals  of  two  years  or  even  less,  so  that  there  is  no  time 
to  work  the  yellow  rattle  seeds  out  of  the  soil  before  the 
favoured  host  plants  are  again  available.  When  once  the 
cereals  are  attacked,  mechanical  methods  of  eradication  can- 
not be  applied,  as  the  parasites  are  so  closely  attached  to  the 
hosts  that  forcible  removal  of  the  yellow  rattle  would  injure 
the  roots  of  the  crop.  Owing  to  the  in  frequency  of  bad  attacks 
of  this  weed  on  arable  land  little  is  known  as  to  the  best 
method  of  cleaning  the  land  ;  fallowing,  coupled  with  frequent 
cultivation  when  the  yellow  rattle  seedlings  appear,  might  do 
some  good.  Possibly,  too,  if  the  land  were  grassed  over  for 
a  time,  and  grazed  by  sheep  as  soon  as  feed  was  available,  a 
clearance  might  be  effected  after  some  years.  It  would  be 
necessary  to  carry  this  on  long  enough  to  allow  most  of  the 
seeds  to  germinate,  and  then  to  keep  a  careful  watch  when 
the  land  was  again  ploughed  up  in  order  to  stamp  out  the 
pest  at  its  first  reappearance. 

RED  BARTSIA  (Bartsia  odontites)  (Fig.  31),  Nat  Order 
Scrophulariacece. — This  partial  parasite  is  rarely  accused  of 
causing  trouble,  but  as  it  is  undoubtedly  parasitic  on  the  roots 
of  wheat  it  should  be  carefully  watched  wherever  it  is  plenti- 
ful. The  roots  of  bartsia  attach  themselves  to  the  wheat  roots 
in  much  the  same  way  as  in  the  case  of  yellow  rattle,  and 
part  of  the  food  is  abstracted  from  the  cereal.  Bartsia  is 
obviously  half  parasitical  on  the  roots  of  various  other  plants, 
as  it  is  often  much  more  abundant  on  the  paths  and  headlands 
than  it  is  among  the  crops.  It  is  seldom  present  in  great 
quantity,  but,  if  conditions  were  specially  favourable,  it  might 
conceivably  do  some  amount  of  mischief. 

Eradication. — No  special  measures  are  taken  to  eradicate 
this  weed,  which  is  usually  kept  in  hand  by  the  ordinary 
methods  of  weed  destruction. 

1  "  The  Eradication  of  Yellow  Rattle  "  (1916  ?),  Agricultural  Department, 
Univ.  Coll.  of  Wales,  Aberystwyth. 


CHAPTER  VII. 

POISONOUS  AND  INJURIOUS  WEEDS. 

THE  most  obvious  damage  done  by  weeds  is  that  to  the  crops 
among  which  they  grow,  but  a  certain  number  of  plants  work 
harm  by  poisoning  or  otherwise  injuring  live  stock  or  human 
beings  or  by  affecting  various  farm  products,  for  instance  milk 
and  wool,  in  such  a  way  as  to  depreciate  their  market  value, 
so  causing  waste  and  loss.  In  some  cases  it  is  probable  that 
damage  from  this  cause  has  been  over-estimated,  but  there  is 
no  doubt  that  it  is  a  point  that  needs  to  be  borne  in  mind  and 
guarded  against  as  far  as  possible.  The  plants  concerned 
may  be  considered  under  two  headings  : — 

(A)  Weeds   that    are    harmful    to  live  stock  and    human 
beings. 

(B)  Weeds  that  injuriously  affect  farm  products. 

(A)  WEEDS  THAT  ARE  HARMFUL  TO  LIVE  STOCK  AND 
HUMAN  BEINGS. 

The  majority  of  these  are  plants  possessing  some  poisonous 
qualities  which  either  cause  death  to  the  animals  eating  them 
or  else  make  the  stock  ill  and  put  them  out  of  condition, 
financial  loss  resulting  in  either  case.  Exact  knowledge  on 
this  subject  is  very  difficult  to  obtain.  The  reports  on  sus- 
pected plants  from  various  sources  are  often  conflicting,  and 
in  most  cases  hardly  anything  is  known  of  the  true  action  of 
the  weeds  concerned.  Also,  it  is  occasionally  to  the  benefit  of 
the  unscrupulous  to  attribute  the  death  of  stock  to  a  poisonous 
weed  rather  than  to  its  true  cause.  Ewart l  sums  up  the 
state  of  affairs  as  follows  :  "  It  is  exceedingly  difficult  or 
impossible  to  draw  a  definite  line  of  demarcation  between 
poisonous  and  non-poisonous  plants.  The  usual  origin  of  the 
report  as  to  the  poisonous  character  of  a  plant  is  that  some 
stock  die,  and  the  nearest  plant  is  selected  as  the  scapegoat, 

1  Ewart,  A.  J.  (1909),  "  The  Weeds,  Poison  Plants,  and  Naturalised  Aliens 
of  Victoria,"  p.  n. 

103 


104  WEEDS  OF  FARM  LAND 

without  any  post  mortem,  experiment,  or  investigation  of  any 
kind.  In  some  cases  this  is  done  purposely  when  the  stock 
have  really  died  from  anthrax  or  similar  diseases.  On  future 
occasions  it  is  usually  easy  to  find  the  suspected  plant  near 
where  the  stock  have  been,  and  so  reports  continue  to  come 
in.  If  the  plant  cannot  be  found,  then  some  other  plant  is 
credited  with  poisonous  properties." 

A  certain  number  of  weeds,  however,  are  credited  with 
causing  harm  the  world  over,  and  there  is  little  doubt  that 
they  are  sources  of  definite  injury  when  they  occur  to  any 
considerable  extent. 

In  "  Plants  Poisonous  to  Live  Stock  "  H.  C.  Long l  includes 
the  following  farm  weeds  that  have  on  occasion  been  found  or 
suspected  to  be  poisonous. 

(a)  Found  Poisonous. — Autumn  crocus,  bindweed,  bracken, 
buttercup,  charlock,  corn  cockle,  darnel,  fool's  parsley,  hem- 
lock, horsetail,  persecaria,  poppy,  radish,  ragwort,  scarlet 
pimpernel,  sheep's  sorrel,  sorrel,  spurge  (various  species),  water 
hemlock  or  cowbane. 

(ft)  Suspected. — Broomrape,  cat's  ear,  dodder,  ground  ivy, 
mayweed,  purging  flax,  silverweed,  sweet  clover,  tormentil, 
viper's  bugloss,  yellow  rattle. 

Although  definite  instances  of  poisoning  have  been  recorded 
from  all  the  plants  in  list  (a)  comparatively  few  of  them  are 
so  virulent  as  to  need  very  special  precautions  with  regard  to 
keeping  stock  out  of  their  way.  The  worst  weeds  are  more 
fully  noticed  in  the  following  paragraphs : — 

Bindweed  (Convolvulus  arvensis). — This  is  seldom  con- 
sidered to  be  harmful,  but  the  underground  stems  are  purgative 
and  the  seeds  are  poisonous  to  stock  if  eaten  in  any  quantity.2 
If  the  seeds  are  ground  up  in  flour  they  are  said  to  render  it 
injurious  to  health,  besides  making  it  a  bad  colour. 

Buttercup  (Ranunculus  sp.*). — Opinions  differ  as  to  the 
harmfulness  of  the  various  species  of  buttercup,  but  many  of 
them  contain  an  intensely  acrid  juice  which  under  some  con- 
ditions, at  least,  may  cause  poisoning  when  the  plants  are  eaten 
by  animals.  Henslow 3  states  that  if  too  many  buttercups  are 
eaten  they  may  cause  death,  but  that  as  drying  dissipates  the 
deleterious  principle  horses  and  cows  may  then  eat  them  with- 

1  Long,  H.  C.  (1917),  "  Plants  Poisonous  to  Live  Stock,"  Cambridge  AgrU 
cultural  Monographs,  Cambridge  University  Press. 
2Ewart,  A.  J.  (1909),  loc.  cit.,  p.  48. 
3  Henslow,  G.  (1901),  "  Poisonous  Plants  in  Field  and  Garden,"  p.  37, 


POISONOUS  AND  INJURIOUS  WEEDS  105 

out  any  injurious  results.  As  a  matter  of  fact,  buttercups  being 
usually  most  plentiful  in  luscious  pastures  where  plenty  of 
more  appetising  food  is  available  the  cattle  thrust  them  aside 
and  do  not  eat  sufficient  to  harm  themselves.  The  degree 
of  toxicity  varies  with  the  stage  of  growth,  as  the  young 
shoots  in  the  spring  are  almost  harmless  in  most  species,  but 
the  amount  of  the  poisonous  substance  increases  as  time  goes 
on,  often  reaching  a  maximum  at  the  time  of  flowering,  the 
blossoms  being  more  poisonous  than  other  parts  of  the 
plants. 

Corn  cockle  (Lychnis  githagd}.  —  The  damage  wrought 
by  this  weed  is  very  generally  recognised,  both  with  regard  to 
its  effect  on  stock  and  on  human  beings.  As  so  often  happens 
the  reports  as  to  its  toxicity  are  very  varied,  but  the  consensus 
of  opinion  brands  corn  cockle  as  productive  of  much  harm. 
The  whole  plant  is  more  or  less  poisonous,  but  the  seeds  are 
by  far  the  most  dangerous  and  most  of  the  trouble  arises 
when  they  are  eaten.  As  they  are  much  the  same  size  as 
wheat  grains  they  are  difficult  to  separate  out,  and  when  they 
are  ground  up  they  give  the  flour  an  unpleasant  greyish  colour, 
and,  if  sufficiently  plentiful,  render  the  bread  injurious  to 
health.  The  poisonous  principle,  githagin,  is  not  supposed 
to  be  destroyed  by  baking,1  or,  even  if  partially  decomposed, 
sufficient  remains  unchanged  to  make  the  bread  harmful,2  and 
fatal  results  have  followed  the  use  of  it.3 

Animals  vary  in  their  response  to  the  action  of  corn  cockle, 
but  from  the  various  experiments  quoted  by  Long  it  is  appar- 
ent that  calves,  pigs,  and  horses  are  very  susceptible,  and  that 
on  the  whole  young  animals  are  more  harmed  than  older  ones. 
It  is  less  certain  how  far  birds  and  poultry  are  affected,  but 
Hungarian  experiments4  have  shown  that  geese  died  when  fed 
with  meal  containing  40  to  50  per  cent,  of  corn  cockle  seeds, 
even  when  this  meal  was  added  to  other  food.  Degen  also 
states  that  corn  cockle  can  produce  grave  symptoms  of  poison- 
ing in  poultry,  the  pathological  symptoms  closely  resembling 
those  of  acute  mineral  poisoning. 

The  weed  is  sometimes  plentiful  in  wheat  crops,  but  as 

1  Henslow,  G.  (1901),  loc.  cit.,  p.  60. 

2  "  Some  Weeds  of  Iowa  "  (1903),  Experiment  Station,  Iowa  State  College, 
Bull.  70. 

3  Long,  H.  C.  (1917),  loc.  cit.,  pp.  19-22. 

4  Degen,  A.  (1916),  Kiserletitgyi  Kozlemenyeh,  XIX,  Part  I,  pp.  11-21.     See 
Internal.  Review  of  Set.  and  Pract.  of  Agric.  (1916),  VII,  pp.  1629-1630. 


106  WEEDS  OF  FARM  LAND 

it  is  a  very  conspicuous  plant  it  can  be  removed  by  hoeing 
or  handpulling  before  the  seeds  ripen.1 

Fool's  parsley  {&thu$a  cynapium}. — A  considerable  differ- 
ence of  opinion  exists  as  to  the  toxic  nature  of  this  weed,  but 
there  can  be  little  doubt  that  it  is  decidedly  poisonous.  Stock 
seem  to  refuse  it  and  so  rarely  suffer  by  it,  but  humans  have 
been  poisoned  by  using  the  leaves  in  mistake  for  parsley.  In 
some  cases  the  consumption  of  the  plant  causes  active  poison- 
ing, in  others  it  is  said  to  be  harmless  ;  it  is  possible  that  this 
contradiction  may  be  due  to  the  fact  that  the  toxic  principle 
or  alkaloid  (coniine)  varies  in  quantity  according  to  the  con- 
ditions of  climate  and  habitat  under  which  the  plant  is  grown, 
or  according  to  the  stage  of  development  in  which  the  weed  is 
eaten.2  Barthe  3  includes  fool's  parsley  among  the  poisonous 
Umbelliferae. 

Hemlock  (Contum  maculatum}. — This  plant  has  long  been 
famed  for  its  poisonous  qualities  and  is  supposed  to  be  the 
source  of  the  decoction  drunk  by  Socrates.  It  is  strongly 
narcotic  an^l  causes  paralysis  and  death.  Probably  hemlock 
has  caused  more  harm  to  human  beings  than  to  farm  animals, 
as  the  leaves  have  been  mistaken  for  parsley,  the  roots  for 
parsnips,  and  the  seeds  have  been  used  in  error  for  anise.4 
Usually  stock  avoid  it  because  of  its  strong  fcetid  odour,  which 
is  especially  marked  when  the  plant  is  bruised.  Goats  seem 
to  be  largely  immune  from  the  action  of  the  poison,5  which  is 
most  abundant  in  the  seeds  but  is  also  present  in  the  stem  and 
leaves.  The  reports  of  the  toxicity  of  hemlock  vary  from 
different  places,  but  according  to  Barthe  6  this  increases  as  one 
passes  from  cold  to  warm  climates,  and  he  states  that  in  North 
Europe  it  can  be  eaten  without  ill  effects.  Whenever  possible 
the  plants  should  be  pulled  up  and  burnt  and  the  ground  kept 
covered  with  other  vegetation  to  prevent  re-establishment  by 
seedlings.  The  seeds  are  said  to  be  very  short-lived  and  in 
this  way  lose  their  vitality  without  the  opportunity  of  germin- 
ating. 

Horsetail  (Equisetum  spp^). — Field  horsetail  (Equisetum 
arvense)  is  the  species  usually  met  with  on  farms,  but  others 

1  A  general  description  and  discussion  of  the  poisonous  qualities  of  corn 
cockle  is  given  in  Jour.  Bd.  Agric.  (1910),  XVII,  pp.  38-45. 

2  Long,  H.  C.  (1917),  loc.  cit.,  pp.  39-40. 

3  Barthe,  L.  (1918),  "  Toxicologie  chimique,"  p.  499. 

4  Long,  H.  C.  (1917),  loc.  cit.,  p.  41-42. 

5  Ewart,  A.  J.  (1909),  loc.  cit.,  p.  29. 
"  Barthe,  L.  (1918),  loc.  cit.,  p.  499. 


POISONOUS  AND  INJURIOUS  WEEDS  107 

occur  as  well,  and  this  may  account  for  the  conflicting  opinions 
as  to  the  poisonous  nature  of  the  weed.  There  can  be  no 
doubt,  however,  that  some  species  of  Equisetum  are  actively 
injurious  to  stock,  and  Equisetum  arvense  is  probably  one  of 
them.  German  feeding  experiments  have  indicated  that  field 
horsetail  (E.  arvense)  is  harmless  to  the  larger  domesticated 
animals,  while  the  marsh  horsetail  (R.  palustre]  is  really  injuri- 
ous to  cattle.  In  America,  on  the  contrary,  it  is  stated  that 
R.  arvense  has  proved  fatal  to  horses,  especially  young  animals.1 
Complaints  of  Equisetum  poisoning  are  fairly  frequent  in  the 
Russian  Agricultural  Press,  horses  and  cattle  suffering  more 
from  the  effects  of  eating  the  plant  dried  (in  hay)  than  green.2 
In  feeding  experiments  dried  Equisetum  arvense  was  mixed 
with  hay,  the  quantity  being  gradually  increased  from  -J- 
to  6  Ib.  per  day.  At  first  the  animals  preferred  it  to  the 
rest  of  their  food,  but  gradually  left  it  alone,  and  after  fourteen 
days  would  hardly  touch  it.  At  the  end  of  this  time  symptoms 
of  poisoning  were  evident,  and  it  was  concluded  that  the  weed, 
to  be  dangerous  to  horses,  must  be  present  in  large  quantities, 
but  might  then  prove  fatal.3  This  is  corroborated  from  Canada, 
as  Howitt  4  states  that  if  fed  in  quantity  in  hay  E.  arvense  is 
poisonous  to  horses.  In  some  parts  of  England,  as  at  Chedzoy, 
on  Sedgemoor,  horsetail  has  a  very  bad  reputation  for  causing 
scour  in  cattle,  but  horses  and  sheep  are  said  to  be  unaffected 
by  it.  As  various  species  are  classed  under  the  popular  name 
it  is  probable  that  some  cause  scouring  and  others  do  not, 
which  may  account  for  the  indifference  with  which  the  plant  is 
regarded  by  farmers  in  some  places  and  the  objection  to  it  in 
others.  Cattle  dislike  the  weed  and  eat  round  the  clumps  in 
order  to  avoid  it  as  far  as  possible.5 

The  presence  of  Equisetum  indicates  poor  drainage,  and  if 
this  is  attended  to  by  deep  ploughing  on  arable  land,  and  by 
underdraining  grass-land,  in  addition  to  keeping  the  water 
courses  clear,  it  is  not  usually  difficult  to  eradicate  the  weed. 

Meadow  saffron  or  autumn  crocus  (Colchicum  autumnale] 


1  See  Long,  H.  C.  (1917),  toe.  cit. ,  pp.  84-85,  for  a  fuller  account  of  this  work. 

2  Trudy  Bjuro  po  prikladnoj  Botanikje,  Jan.,  1916  ;  see  your.  Bd.  Agric., 
XXIII,  p.  278. 

3  "  Horse  Poisoning  by  Equisetum  arvense  "  (1912),  Kew  Bull.  Misc.  Inform., 
No.  3  ;  see  your.  Bd.  Agric.,  XIX,  p.  229. 

4  Howitt,  J.  E.  (1916),  "  Weeds  of  Ontario,"  Ontario  Dept.  of  Agric.,  p.  22. 

5  Brenchley,  W.  E.  (1916-17),  "  West  Country   Grass-lands,"  your.  Bath 
and  West  and  Southern  Counties  Soc.,  XI,  p.  97. 


io8  WEEDS  OF  FARM  LAND 

(Fig.  32). — This  plant  is  local,  but  very  abundant  when  it 
occurs,  and  is  one  of  the  most  poisonous  of  our  British  farm 
weeds,  numerous  cases  of  loss  of  stock  having  been  traced  to 
it.  In  Switzerland  l  cases  of  poisoning  of  household  animals 
and  human  beings  are  recorded  every  year.  Horses  are 
poisoned  by  the  green  plant  or  by  dried  leaves  in  hay.  Cattle 
usually  avoid  it  in  any  form,  though  young  animals  are  fre- 
quently poisoned.  Poisoning  often  occurs  in  the  spring  when 
beasts  fed  in  the  stall  during  the  winter  are  let  out  on  the 
young  grass.  Pigs  are  affected,  but  sheep  and  goats  seem  to 
be  more  or  less  immune.  The  flowers  appear  alone  in  the 
autumn,  no  leaves  being  then  produced,  and  the  seed  vessel 
remains  below  the  soil.  After  the  flowers  die  down  no  more 
is  seen  of  the  plant  till  the  following  spring,  when  leaves  ap- 
pear and  the  seed  vessel  rises  out  of  the  ground.  Every  part 
of  the  plant  is  poisonous,  corm,  leaves,  flowers,  and  seeds,  so 
that  danger  to  stock  occurs  both  in  autumn  and  spring.  Oc- 
casionally, if  the  spring  is  late,  the  leaves  may  appear  in  hay 
and  so  cause  trouble,  but  generally  it  is  grazing  stock  that  are 
liable  to  be  affected.  Grazing  is  safe  enough  in  the  summer 
and  winter  while  the  plant  is  resting,  but  during  the  spring 
and  autumn  stock  should  be  rigidly  excluded  from  fields  con- 
taining the  weed.  The  toxic  principle,  colchicine,  is  not 
volatile  and  is  not  removed  by  drying  the  plants,  so  that  the 
leaves  are  as  harmful  in  hay  as  when  fresh,  and  as  the  poison 
seems  to  be  cumulative  repeated  small  doses  may  eventually 
cause  poisoning.2  Warm  milk  has  been  recommended  as  an 
antidote.  With  perseverance  meadow  saffron  can  be  easily 
eradicated  ;  seeding  may  be  prevented  by  dragging  a  crossbeam 
with  bundles  of  brushwood  and  bushes  attached,  over  the 
meadow  when  the  plants  are  flowering,  thus  destroying  the 
blossoms,3  while  the  corms  can  be  weakened  and  starved  out 
by  cutting  and  handpulling  the  leaves  in  spring.  A  special 
digging  iron  for  the  destruction  of  the  corms  has  also  been 
employed. 

Purging  flax  (Linum  catharttcum)  (Fig.  33). —  This  is 
regarded  as  a  suspected  plant  only  by  Long,  but  it  has  often 
been  known  to  occur  in  meadows  or  in  hay  which  has  caused 

1  Stebler    and    Schroeter,    Matten  und   Weidcn   der  Schweiz,  IX,  p.  209, 
Summ.  in  Jour.  Bd.  Agrlc.  (1908),  XV,  p.  303. 

2  (1908),  "  Meadow  Saffron,"  Jour.  Bd.  Agrlc.,  XV,  pp.  44-45. 

3  (a)  Illustrierte  Landwirtschaftliche  Zeitung,  No.  27  (1912),  (6)  Bornemann, 
"  Die  wichtigsten  landwirtschaftlichen  Unkrauter,"  p.  68  (see  Jour.  Bd.  Agric. 
(1913),  XIX,  p.  852). 


POISONOUS  AND  INJURIOUS  WEEDS  109 

purging  or  death  to  the  animals  fed  thereon.     Under  some  con- 
ditions prussic  acid  is  developed  by  the  plant  and  this  would 


FIG.    32.  —  AUTUMN      CROCUS  FIG.  33. — PURGING  FLAX  (Linwn  catharticum). 

(Colchicum  autumnale). 

be  quite  sufficient  to  cause  the  results  recorded ;  therefore 
it  is  wiser  to  regard  with  suspicion  pastures  or  meadows  con- 
taining this  flax. 

Ragwort  (Senecio  jacobcea). — The  harmful   nature   of  this 


no  WEEDS  OF  FARM  LAND 

weed  is  not  often  recognised  in  England,  probably  because 
the  first  symptoms  of  poisoning  are  so  insidious,  but  the 
Board  of  Agriculture  has  called  attention  to  the  fact  as  the 
danger  of  loss  is  considerable.1  In  Australia,2  New  Zealand, 
and  Canada,3  however,  ragwort  is  considered  a  very  bad  weed 
as  it  induces  a  fatal  disease,  cirrhosis  of  the  liver.  The  symp- 
toms only  appear  after  one  to  three  months  continuous  grazing 
on  the  plant,  and  even  if  the  cattle  are  removed  while  they 
still  appear  healthy,  after-symptoms  may  manifest  themselves, 
leading  to  fatal  results.  Horses  and  cattle  suffer  badly,  but  it 
is  uncertain  whether  sheep  are  affected.  Probably  the  plant  is 
most  actively  poisonous  in  June,  July,  and  August,  and  as  there 
is  no  known  cure  it  is  essential  that  ragwort  should  be  eradicated 
from  pasture  land  and  not  allowed  to  enter  into  hay.  This 
can  be  done  (i)  by  grazing  with  sheep  in  winter  or  early  spring 
before  much  growth  has  been  made,  (2)  by  cutting  the  plants 
in  the  flowering  stage,  the  cut  portions  being  gathered  up  and 
burned,  (3)  by  handpulling  early  in  July.  The  plant  being 
biennial  eradication  must  be  carried  on  for  two  years,  and 
watch  must  also  be  kept  against  fresh  infestation  by  seeds 
carried  by  the  wind. 

Shepherd's  purse  (Capsella  bursa-pastoris}. — This  is  rarely 
considered  to  be  poisonous,  but  a  case  is  on  record  in  which 
two  children  were  poisoned  by  eating  the  tops  of  the  plants,4 
their  lives  being  saved  with  difficulty.  This  does  not  neces- 
sarily imply  that  shepherd's  purse  is  poisonous  in  the  ordinary 
way,  as  certain  individuals  are  often  adversely  affected  or 
poisoned  by  foods  that  are  harmless  to  most  people,  e.g.  some 
people  are  unable  to  eat  strawberries  without  suffering  from  a 
type  of  poisoning. 

Water  hemlock  or  cowbane  (Cicuta  virosa). — This  is  not  in 
reality  an  arable  or  grass-land  weed,  but  as  it  is  exceedingly 
poisonous  and  may  be  found  in  damp  areas  or  water  courses 
to  which  stock  can  gain  access,  it  must  not  be  left  out  of  con- 
sideration. Happily  it  is  not  very  common  or  abundant  in 
this  country,  but  in  other  parts  of  the  world  it  flourishes  and 
special  precautions  have  to  be  taken  against  it.  The  greater 
part  of  the  poisonous  principle  is  present  in  the  rhizomes  or 

1  "  Poisoning  of  Cattle  by  Ragwort"  (1917),  Jour.  Bd.  Agric.,  XXIV,  pp. 
433-436. 

2  Ewart,  A.  J.  (1909),  loc.  cit.,  p.  42. 
3Howitt,  J.  E.  (1916),  loc.  cit.,  p.  95. 

4  Kellerman,  W.  A.  (1895),  "  Poisoning  by  Shepherd's  Purse,"  Bot.  Gaz., 
XX,  pp.  325-326. 


POISONOUS  AND  INJURIOUS  WEEDS  in 

underground  stems,  and  possibly  these  are  the  only  parts  of 
the  plant  that  are  actually  poisonous  as  it  is  said  that  the 
stems  and  leaves  can  be  eaten  in  quantity  with  impunity.1 
The  poison  is  very  rapid  in  its  action,  the  first  symptoms  ap- 
pearing in  about  twenty  or  forty  minutes,  and  death  resulting 
if  a  fatal  dose  has  been  swallowed.  Wherever  water  hemlock 
is  known  to  occur  the  plants  should  be  grubbed  out  and  burned  ; 
great  care  being  taken  not  to  leave  any  portions  of  the  rhiz- 
omes lying  about  where  animals  can  get  them.  The  pulled 
plants  should  not  be  left  in  the  water  as  the  toxic  principle, 
cicutin,  dissolves  out  and  contaminates  it,  thus  giving  rise 
to  another  source  of  trouble.2 

In  addition  to  the  above  outstanding  weeds  there  are  a 
few  which  are  certainly  poisonous  or  otherwise  harmful,  but 
which  are  only  locally  or  occasionally  present  in  sufficient 
quantity  to  cause  trouble. 

Sheep's  sorrel  (Rumex  acetosella)  is  charged  8  with  having 
poisoned  a  horse  and  sheep  which  browsed  upon  it  when  the 
fruit  was  ripe  and  full  of  seeds,  with  fatal  results  to  the  horse. 
The  nature  of  the  poisonous  principle,  if  any,  is  not  known, 
unless  the  toxic  action  was  due  to  the  acid  oxalates  that  are 
present  in  the  plants.  Spurges  (Euphorbia  spp.}  are  usually 
avoided  by  stock,  but  if  eaten  are  harmful  as  the  juice  is  acrid 
and  the  seeds  contain  an  extremely  purgative  oil.  Stagger 
weed  (Stachys  arvensis)  seldom  occurs  in  any  quantity  in  Eng- 
land, but  in  the  Dominions  it  is  reported  as  causing  serious 
trouble  among  cattle.4  It  is  a  weed  of  damp  places  and  may 
be  eradicated  by  draining.  Black  nightshade  {Solanum  nig- 
rum)  sometimes  does  mischief,  and  Barthe  states  that  it  is 
poisonous  in  warm  and  temperate  regions,  but  loses  its  poison- 
ous properties  in  the  cold  northern  regions.5 

Without  being  actually  poisonous  some  weeds  may  cause 
trouble  if  they  are  eaten  or  handled  Broomrape  (Orobanche 
minor]  has  been  found  to  produce  colic  in  animals  fed  on 
clover,  in  which  it  grows  plentifully,  while  the  seeds  of  black 
bindweed  (Polygonutn  convolvulus)  may,  after  some  time,  cause 

1  Fleming,  C.  E.  (1918),  "  Range  Plants  Poisonous  to  Sheep  and  Cattle  in 
Nevada,'M^nc.  Exp.  Stat.,  Univ.  of  Nevada,  Bull.  No.  95,  p.  23. 

2  Smith,  J.  D.  (1917),  "  Weeds  of  Alberta,"  Bull.  No.  2,  Province  of  Alberta, 
Depart,  of  Agric.,  Seed  and  Weed  Branch,  p.  98. 

3  Henslow,  G.  (1901),  he.  cit.,  p.  142. 

4  Maiden,  J.   H.   (1916),    "  Asphodelus    fistulosus    and   Stachys   arvensis : 
Harmful    Weeds    in    New    South  Wales,"   Agric.    Gaz.,  New  South    Wales, 
XXVIII,  pp.  335-338. 

5  Barthe,  L.  (1918),  "  Toxicologie  chimique,"  p.  518. 


H2  WEEDS  OF  FARM  LAND 

serious  internal  derangements  if  too  many  are  present  in  the 
oats  fed  to  stock.1  In  Belgium,  hogweed  (Heracleum  sphon- 
dylium)  is  supposed  to  have  caused  "  Panaisie,"  a  kind  of 
erysipelas  induced  if  the  plants  are  rooted  up  when  they  are 
covered  with  dew.  No  harm  results  when  hogweed  is  pulled 
later  in  the  day,2  because  then  the  dew,  in  which  it  is  suggested 
that  an  irritant  essential  oil  is  dissolved,  has  been  dissipated 
by  the  sun. 

Occasionally  mechanical  injury  is  caused  by  local  irritation 
due  to  very  rough  or  sharp  weeds  or  by  the  accumulation  of 
indigestible  masses  in  the  alimentary  canal.  Huffcaps  (Aira 
ccespitosa]  is  an  exceedingly  coarse  and  rough  grass  and  rasps 
the  mouth  badly,  and  in  places  where  it  occurs  a  clause 
is  inserted  in  many  leases  to  the  effect  that  the  land  must 
be  kept  clear  of  it  by  cutting  or  otherwise.3  The  sharp 
awns  of  certain  grasses,  as  wild  barley  and  brome,  tend  to  pene- 
trate the  gum  and  break  off,  giving  rise  to  considerable  inflam- 
mation, and  if  the  heads  are  swallowed  they  may  accumulate  or 
"  ball "  in  the  stomach  of  the  animal.  The  fibres  of  shepherd's 
purse  and  the  much  branched  chickweed  are  liable  to  cause 
trouble  in  the  same  way  if  they  are  eaten  too  freely. 

(B)  WEEDS  THAT  INJURIOUSLY  AFFECT  FARM  PRODUCTS. 

The  milk  of  cows  and  the  flesh  of  stock  is  liable  to  become 
tainted  if  any  strong  smelling  or  strong  tasting  plant  is 
included  in  the  animals'  food,  and  many  complaints  of  un- 
pleasant flavours  have  been  traced  to  this  source.  There  are 
not  a  large  number  of  weeds  that  are  proved  to  taint  farm 
products,  but  some  of  these  have  been  in  bad  repute  from  early 
days.  In  1789  Adam 4  included  dyer's  weed  (Reseda  sp.\  darnel 
(Lolium  temulentum),  cow-wheat  (Melampyrum  j/.),  melilot 
(Melilotus  sp.)y  and  crow  garlic  among  the  weeds  that  spoil  farm 
products,  and  most  of  these  had  been  known  for  long  before. 

Crow  garlic  (Allium  vineale]  (Fig.  34)  and  ramsons  (A. 
ursinum)  (Fig.  35)  bear  the  worst  reputation  for  tainting  milk 
and  for  injuring  wheat  and  flour.  Crow  garlic  is  difficult 
to  distinguish  among  grass  until  it  flowers,  as  the  leaves  are 
very  narrow,  so  that  suspected  pastures  should  be  very  carefully 
examined  before  stock  is  turned  in  in  the  spring.  Although 

1  Henslow,  G.  (1901),  loc.  cit.,  p.  141.  *Ibid.,  pp.  99-100. 

3Brenchley,  W.  E.  (1916-17),    "West  Country  Grass-lands,"  ibid.,  p.  97. 
4  Adam,  J.  (1789),  "  Of  Weeds,"  "  Practical  Essays  in  Agriculture,"  II,  pp. 
173-198. 


POISONOUS  AND  INJURIOUS  WEEDS  113 

the  tainting  of  milk  and  butter  is  universally  admitted,  opinions 
differ  as  to  how  the  mischief  is  worked.     Some  people  hold  that 


FIG.  34.  —  CROW  GARLIC  FIG.  35. — RAMSONS  (A Ilium  ursinum). 
(A  Ilium  vinealc),  show- 
ing underground  bulb 
with  bud  and  cluster  of 
aerial  bulbils  on  the 
flowering  stalk. 

it  is  entirely  due  to  dirty  milking,  whereby  small  pieces  of  garlic 
leaves  fall  into  the  pail,  but  that  this  is  the  explanation  is 
improbable  in  the  majority  of  cases.  Some  farmers  hold  that 
garlic  taints  the  breath  of  cows,  as  it  does  that  of  man,  and  that 

8 


ii4  WEEDS  OF  FARM  LAND 

in  some  way  or  other  this  influences  the  milk,  but  this  again  is 
highly  improbable.  It  is  far  more  likely  that  the  direct  taint  is 
imparted  to  the  milk  in  some  physiological  manner  not  well 
understood,  and  possibly  the  taint  is  carried  in  the  fat  globules 
more  readily  than  in  the  rest  of  the  milk.  One  dairy  farmer 
known  to  the  author  has  fed  cows  on  "garlic  wheat  "  or  even  on 
"  garlic  with  wheat  in  it  "  and  had  no  suspicion  of  trouble  nor 
complaints  of  the  milk  being  tainted.  In  American  experi- 
ments l  it  has  been  found  that  increasing  the  length  of  time 
between  feeding  on  the  onion  and  the  hour  of  milking  reduced 
the  unpleasant  odour  and  flavour.  There  is  only  a  slight  odour 
and  flavour  in  milk  when  cows  are  kept  off  onion  infested  pas- 
tures for  four  hours  before  milking  and  this  slight  flavour  is  said 
to  disappear  almost  entirely  when  the  milk  stands  for  four  hours. 
Even  if  this  be  so  it  is  wiser  to  keep  milking  cows  out  of  fields 
known  to  be  infested  with  garlic  during  the  growing  period  of 
the  plant  in  spring  and  early  summer.  There  is  an  idea  among 
graziers  that  store  beasts  and  cattle  may  safely  be  run  in  these 
fields,  the  garlic  often  acting  as  a  mild  tonic  or  aperient,  but 
that  fattening  sheep  and  cattle  should  be  kept  away  lest  their 
flesh  become  tainted. 

Crow  garlic  is  occasionally  a  pest  on  arable  land,  and  as 
the  aerial  bulblets  are  about  the  same  size  as  wheat  grains  it 
is  difficult  to  separate  the  two,  and  the  value  of  the  wheat  is 
thereby  depreciated.  Bread  made  from  garlicky  flour,  especi- 
ally if  eaten  warm,  has  a  pronounced  odour  and  flavour,  and 
in  the  United  States  it  is  estimated  that  the  money  loss  from 
wild  onion  runs  into  millions  of  dollars  yearly.2 

Ramsons  is  closely  allied  to  the  crow  garlic  and  sometimes 
causes  similar  trouble.  It  is  readily  distinguished  by  its  thin, 
flat  spreading  leaves,  and  when  it  is  abundant  in  the  shady 
places  it  prefers  the  milk  of  cows  that  gain  access  to  it  becomes 
badly  tainted,  and  it  is  said  that  the  flavour  is  strongly  ac- 
centuated if  the  milk  is  scalded. 

Darnel  (Lolium  temulentuin)  is  possibly  the  "  tares  "  of 
Scripture,  and  its  harmful  nature  has  been  known  for  centuries. 
It  sometimes  grows  freely  among  wheat  ;  the  seed  being 
nearly  as  large  as  wheat  it  is  difficult  to  separate  the  two,  with 
the  result  that  the  darnel  discolours  the  flour  and  gives  a  dis- 
agreeable taste  to  the  bread.  Under  some  circumstances  the 


H.  R.  (1918),"  Wild  Onion,  Method  of  Eradication,"  p.  n,  C7.S.4-, 
Depart,  of  Agric.,  Farmer's  Bull,  610, 
2/^.,p.  3. 


POISONOUS  AND  INJURIOUS  WEEDS  115 

weed  is  not  merely  unpleasant  but  dangerous,  and  cases  of 
human  and  stock  poisoning  have  been  known  to  occur.  Adam J 
states  that  the  seeds  possess  a  very  intoxicating  quality  and 
bring  on  convulsions  if  taken  in  large  quantities,  and  in  France 
darnel  is  called  Ivraie  because  when  brewed  with  barley  it 
acts  as  a  narcotic  intoxicant2 

Melilot  (Melilotus  spp.}  occasionally  occurs  as  a  weed  in  this 
country,  though  in  America  and  elsewhere  it  is  grown  for 
fodder.  Ewart3  states  that  the  sweet  smelling  cumarin, 
which  all  the  species  contain,  in  excess  produces  a  disinclina- 
tion to  locomotion,  paralysis  and  ultimately  fatal  symptoms, 
but  that  no  harm  is  likely  to  occur  if  the  amount  of  melilot 
present  does  not  exceed  10  per  cent,  of  the  herbage.  Accord- 
ing to  Adam,4  if  the  seeds  are  ground  with  the  corn  they  spoil 
the  flour,  as  the  bread  made  from  it  has  a  strong  taste  and 
smells  like  melilot  plaister. 

Pennycress  or  stinkweed  (Thlaspi  arvense). — Complaints  of 
this  weed  are  not  often  heard  in  this  country,  because  it  seldom 
happens  that  it  is  abundant  enough  to  work  harm,  but  in  the 
Dominions  it  is  regarded  as  most  noxious  and  special  measures 
are  adopted  against  it.  The  whole  plant  has  a  peculiarly 
objectionable  odour,  somewhat  resembling  that  of  garlic,  and 
the  seed  is  very  pungent.  The  stinkweed  taints  milk  and 
butter  and  also  the  flesh  of  animals  that  eat  it,  causing  con- 
siderable loss  where  the  weed  is  plentiful.5 

Various  other  weeds  are  accused  of  tainting  milk  and 
butter,  but  the  evidence  in  many  cases  is  less  clear,  and  pos- 
sibly local  conditions  of  soil  and  climate  may  make  a  species 
harmful  in  some  cases  and  innocuous  in  others.  Among  the 
accused  weeds  are  buttercups,  wild  mustard  and  charlock,6 
yarrow,  dog  daisy,  chamomile  and  mayweed,7  while  woodwax 
(Genista  tinctorid]  is  supposed  to  make  milk  bitter. 

The  hooked  fruits  or  burs  of  various  weeds  when  abundant 
are  another  source  of  loss  to  the  farmer.  These  burs  stick 
to  the  wool  of  sheep  as  the  animals  rub  against  them,  and 
it  is  impossible  to  extricate  them  from  the  fleeces  without 

1Adam,  J.  (1789),  loc.  cit.,  p.  188. 

2  Long,  H.  C.  (1917),  loc.  cit.,  p.  83. 

3  Ewart,  A.  J.  (1909),  loc.  cit.,  p.  23. 

4  Adam,  J.  (1789),  loc.  cit.,  p.  192. 

5  Henderson,   T.  B.   R.  (1909),  "  Stinkweed,  How  ,to  Hold  it  in  Check," 
Press  Bull.   No.  2,  Province  of  Alberta,  Depart,  of  Agric. 

6  F.  M.  (1910),  "  Crucifers  and  Milk,"  Revue  Scientifique,  p.  599. 

7  Long,  H.  C.  (1917),  loc.  cit.,  p.  101. 

8* 


n6  WEEDS  OF  FARM  LAND 

wasting  a  considerable  amount  of  wool.  Cleavers,  corn 
buttercup,  geum,  agrimony,  and  other  plants  that  depend  upon 
animals  for  their  distribution  all  contribute  to  this  loss,  and 
where  sheep  are  kept  it  is  very  important  that  special  care 
should  be  taken  in  the  eradication  of  this  type  of  weed. 


CHAPTER  VIII. 

ARABLE  WEEDS.     ASSOCIATION  WITH  SOILS. 

I.  GENERAL. 

IN  travelling  about  the  country  and  inspecting  fields  in  various 
districts  the  first  impression  received  is  that  the  individuals  of 
the  weed  flora  are  very  closely  determined  by  the  type  of  soil 
on  which  they  grow.  Sandy  land  is  often  smothered  with 
poppies,  spurry  or  corn  marigold,  boggy  soil  is  carpeted  with 
willowweed,  chalk  shows  abundance  of  chicory,  and  loam  and 
clay  present  a  general  mixture  of  weeds  without  any  great 
outstanding  species.  A  closer  investigation  shows  that  this 
first  impression  is  to  a  large  extent  erroneous,  that  most 
individual  species  of  weeds  may  be  found  on  different  kinds  of 
soils  in  various  parts  of  the  country  and  that  comparatively 
few  weeds  are  definitely  associated  with  any  particular  soil. 
Still  closer  examination  of  the  weed  populations  shows  that  as 
a  general  rule  the  weed  communities  are  far  more  characteristic 
of  the  different  soils  than  are  the  individual  species.  The 
communities  vary  within  themselves  in  different  localities,  but 
in  their  broad  outlines  they  show  some  connection  with  the 
character  of  the  soil.  It  is  probable  that  many  factors  interact 
to  determine  the  nature  of  the  weed  population,  and  that  the 
mere  chemical  or  mechanical  composition  of  the  soil  is  of 
comparatively  little  importance  except  in  so  far  as  it  is  bound 
up  with  other  factors  such  as  drainage,  rainfall,  temperature, 
season,  acidity,  and  aeration.  The  interaction  of  all  these 
factors  determines  the  relative  competition  of  the  species 
growing  on  the  soils,  and  so  the  personnel  of  the  weed  com- 
munities is  profoundly  affected.  The  influence  of  factors  other 
than  soil  is  often  well  shown  by  the  difference  in  the  propor- 
tions between  the  weeds  that  grow  in  wet  seasons  and  dry 
seasons.  If  the  season  be  very  wet  some  plants  gain  the 
upper  hand  at  an  early  date  and  maintain  their  position  all 
through^the  year,  whereas  if  the  season  be  dry  quite  another 
set  of  plants  comes  to  the  front  on  the  same  soil. 

117 


u8  WEEDS  OF  FARM  LAND 

The  whole  question  of  weed  population  probably  resolves 
itself  into  one  of  competition  between  the  different  species. 
The  absence  of  a  weed  in  any  particular  situation  may  be  due 
to  one  of  several  reasons : — 

(1)  The  plant   is  so  unsuited  to  the  soil  that  it  will  not 
flourish  on  it  under  any  circumstances. 

(2)  Other  species  are  so  much  more  favoured  by  the  con- 
ditions   of  growth   that    the   particular  species    concerned  is 
smothered  out  and  is  unable  to  make  any  headway. 

(3)  The  method  of  cultivation  may  be  such  as  to  hinder 
the  species  from  establishing  itself. 

(l)  It  very  frequently  happens  that  a  species  is  absent 
from  a  particular  type  of  soil  in  one  place  while  it  is  present  or 
even  abundant  upon  similar  soil  in  other  districts.  The  con- 
clusion may  be  drawn  that  comparatively  few  plants  are  really 
antipathetic  to  any  soil,  and  that  if  other  conditions  are  suit- 
able most  plants  will  grow,  at  least  to  some  extent,  on  any 
kind  of  soil.  Naturally,  there  are  exceptions  to  this  rule,  but 
they  are  probably  less  frequent  than  they  seem  at  first  sight. 
Salt  marshes  are  characterised  by  a  specialised  set  of  plants 
adapted  to  the  peculiar  conditions  induced  by  the  flooding 
with  salt  water  which  occurs  at  high  tides.  These  species, 
as  Salicornia  spp.,  Suceda  maritima  and  S.  fruticosa,  Aster 
tripolimn,  Glaux  maritima  and  several  others  are  never 
found  as  weeds  of  cultivation  or  in  any  inland  area.  Never- 
theless it  is  quite  possible  to  grow  them  in  ordinary  soil 
and  to  obtain  good  plants.  On  the  other  hand,  the  salt 
marsh  conditions  are  so  exceedingly  abnormal  that  the 
majority  of  land  plants  find  it  impossible  to  live  in  such  situ- 
ations, because  the  combination  of  waterlogging,  flooding, 
and  an  excess  of  salt  render  the  position  untenable.  But,  as 
soon  as  the  land  is  drained  and  the  floods  are  kept  back  by 
dykes  the  typical  land  plants  soon  find  entrance  and  before 
long  oust  the  original  occupants  of  the  soil. 

Sorrel  and  sheep's  sorrel  are  usually  associated  with  acid 
soil,  and  it  is  sometimes  asserted  that  they  will  not  grow  in 
the  presence  of  a  sufficient  supply  of  lime.  Rothamsted  ex- 
periments have  shown  that,  in  the  absence  of  competition  of 
other  plants,  these  species  do  better  with  a  full  supply  of  lime 
than  they  do  on  an  acid  soil.  Pot  cultures  were  carried  on 
with  a  light  soil,  'deficient  in  lime.  The  amount  of  chalk 
necessary  to  correct  the  acidity  of  the  soil  was  determined 
and  then  calcium  carbonate  was  added  to  the  pots  in  varying 


ARABLE  WEEDS.     ASSOCIATION  WITH  SOILS      119 


proportion  so  that  a  series  was  obtained  containing  J,  J,  f ,  I 
and  twice  the  amount  of  chalk  really  required.  Various  seeds 
were  sown,  including  grasses,  Rumex  acetosa,  R.  acetosella,  and 
Trifolium  pratense,  and  in  addition  a  mixture  of  all  the  seeds 
was  made  and  sown  in  big  pots  prepared  with  soil  similar  to 
that  in  the  small  pots.  The  plants  were  all  kept  under  the  same 
conditions  in  a  glass  house  and  were  carefully  watered.  At 
the  close  of  the  experiment  the  plants  were  cut,  weighed 
green,  dried  thoroughly  and  weighed  again.  It  was  found 
that  by  far  the  heaviest  crop  of  Rumex  acetosa  was  obtained 
from  the  pots  that  received  twice  as  much  chalk  as  was  needed, 
and  that  the  weight  of  the  crop  was  rather  less  in  the  more 
acid  soils  than  in  those  pots  which  had  received  a  complete 
dressing  of  chalk,  thus  disproving  the  statement  that  sorrel 
prefers  an  acid  soil  to  one  containing  a  sufficiency  of  lime. 

Rumex  acetosa. 


Lime  Requirement  (Supplied  as  Chalk). 

o 

\ 

i 

1 

i 

2 

gms. 

gms. 

gms. 

gms. 

gms. 

gms. 

Average  green  weight  per  pot    . 

10-85 

97 

"*5 

I2'9 

12-5 

2I'O 

Average  dry  weight  per  pot 

2'I 

175 

2-17 

2*1 

2-43 

3'8 

The  sheep's  sorrel  germinated  very  badly  in  all  the  pots 
and  only  one  or  two  plants  grew  at  all.  The  only  pots  in 
which  any  fair  amount  of  growth  was  made  were  two  which 
had  received  f  and  a  full  supply  of  lime,  thus  again  showing 
that  this  species  will  grow  well  on  soils  which  are  not  acid. 

All  the  other  species  grown  alone  made  satisfactory  growth 
in  the  soils  of  varying  acidity,  as,  owing  to  the  absence  of 
competition,  they  were  able  to  make  the  most  of  the  soil  even 
though  it  were  not  really  very  congenial.  In  the  big  pots, 
on  the  other  hand,  the  proportions  of  the  various  species  varied 
with  the  acidity,  indicating  that  directly  competition  came  into 
play  the  plants  that  were  most  favoured  by  their  particular 
soil  gained  the  upper  hand,  while  the  species  that  were  more 
indifferent  suffered  by  the  crowding  of  the  other  plants  and 
consequently  developed  less  strongly. 

The  explanation  of  the  discrepancy  between  the  results  of 
these  pot  cultures  and  the  ordinary  field  observations  probably 
lies  in  the  mere  fact  of  the  varying  conditions  of  competition 
between  the  plants.  Acid  conditions  of  soil  are  not  particularly 


126  WEEDS  OF  FARM  LAND 

favourable  to  the  growth  of  most  species,  but  Rumex  acetosella 
is  quite  indifferent  to  them.  Consequently,  while  most  plants 
are  hesitating  to  start  boldly  into  growth  the  sheep's  sorrel 
pushes  ahead,  dominates  the  situation  from  the  first  and  holds 
its  own  to  such  an  extent  that  many  of  the  other  weeds  do  not 
have  a  fair  chance  to  make  a  start.  On  ordinary  soils,  how- 
ever, the  competition  is  keen  from  the  beginning.  Sheep's 
sorrel  would  be  quite  content  with  the  soil  conditions,  but  it 
cannot  put  up  with  the  competition  of  other  species,  and  con- 
sequently it  gets  crowded  out  of  existence.  This  does 
not,  of  course,  imply  that  if  competition  were  removed 
sheep's  sorrel  would  spring  up  everywhere,  as  seeds  would 
not  be  present  in  every  soil.  In  the  general  distribution  of 
species  the  balance  has  been  continually  adjusted,  until  now 
a  few  species  are  very  specially  associated  with  particular  soils 
while  the  great  majority  of  plants  will  grow  everywhere  if 
conditions  are  favourable.  Thus  the  struggle  for  existence  is 
continually  going  on  and  the  balance  of  dominating  species  is 
shifting  day  by  day  in  response  to  the  perpetual  changing  of 
the  conditions  which  favour  or  inhibit  growth. 

This  being  the  case,  very  few,  if  any,  arable  weeds  can  be 
regarded  as  symptomatic  of  the  soil  on  which  they  grow — i.e. 
there  are  practically  no  individual  species  which  indicate 
infallibly  the  nature  of  the  land  where  they  occur.  Individual 
species  are  therefore  of  little  use  as  decisive  indicators,  but 
communities  of  species  give  much  more  accurate  information. 
For  instance,  the  presence  of  sheep's  sorrel  indicates  acidity 
of  soil,  though  it  does  not  necessarily  show  whether  the  land 
is  heavy  or  light,  but  if  it  is  associated  with  spurry  and  annual 
knawel  the  community  or  association  of  species  shows  definitely 
that  the  soil  is  very  light  or  sandy  in  addition  to  being  acid. 
Again,  though  no  single  weed  is  exclusively  associated  with 
clay  land,  the  presence  of  such  a  mixture  of  weeds  as  black 
bent,  hoary  plantain,  corn  buttercup,  coltsfoot,  and  couch-grass 
at  once  indicates  a  heavy  soil.  In  considering  the  association 
of  weeds  with  soil,  therefore,  it  is  necessary  to  lay  more  stress 
pn  the  particular  communities  in  which  the  plants  occur  than 
on  the  connection  of  one  particular  species  with  one  definite 
type  of  land. 


CHAPTER  IX. 

ARABLE  WEEDS.     ASSOCIATION  WITH  SOILS. 

II.   SPECIAL. 

IN  order  to  get  some  definite  idea  of  the  association  of 
weeds  with  crops  and  soils  from  the  statistical  point  of  view 
weed  surveys  have  been  carried  on  for  several  years  in  differ- 
ent parts  of  the  country.  In  the  course  of  the  investigations 
many  hundreds  of  fields  have  been  visited,  the  crops  and  the 
nature  of  the  soil  observed,  and  detailed  notes  made  of  every 
weed  occurring  on  each  field  with  its  relative  abundance  or 
scarcity.  The  results  thus  obtained1  have  been  carefully 
analysed  and  compared,  and  have  provided  the  figures  on  which 
are  based  the  observations  made  in  the  present  chapter.  The 
weed  survey  is  preliminary  and  incomplete  as  it  only  deals 
with  a  limited  number  of  districts,  and  the  conclusions  put 
forward  may  be  subject  to  modification  when  more  data  become 
available  from  other  parts  of  the  country.  The  variety  of  soils, 
however,  is  considerable,  the  areas  worked  were  far  apart 
(ranging  from  Somerset  to  Norfolk),  and  the  correspondence 
in  the  results  from  the  different  districts  is  sufficiently  close  to 
justify  the  belief  that  later  modifications  will  be  matters  of 
detail  rather  than  of  principle. 

In  considering  the  association  of  particular  weeds  with 
special  types  of  soil  the  remarks  made  in  the  previous  chapter 
should  always  be  borne  in  mind.  A  plant  may  be  more  or 
less  characteristic  of  a  certain  soil  when  it  occurs  in  any 
quantity,  and  yet  it  may  be  present  on  every  other  type  of 

iBrenchiey,  W.  E.  (1911),  "The  Weeds  of  Arable  Land  in  Relation  to  the 
Soils  on  which  they  Grow,"  I  (Bedfordshire),  Ann.  Bot.,  XXV,  pp. 
155-165. 

(1912)  Ibid.,  II  (Wiltshire  and  Somerset),  Ann.  Bot.,  XXVI,  pp.  95-109. 

(1913)  Ibid.,  Ill  (Norfolk),  Ann.  Bot.,  XXVII,  pp.  141-166. 

(1915)     "  Weeds  on  Arable   Land  and  their  Suppression "    (Nottinghamshire 

and  Derbyshire),  Jour.  Roy.  Agric.  Soc.,  Vol.  76,  pp.  14-37. 
(1916-17)  "  West  Country  Grass-lands,"   Jour.   Bath  and  West  and  Southern 
Counties  Society,  XI,  pp.  85-112. 


122  WEEDS  OF  FARM  LAND 

soil  to  some  extent,  or  it  may  be  absent  in  one  district  from 
the  very  soil  on  which  it  is  so  characteristic  elsewhere.  Con- 
sequently exceptions  will  be  found  to  nearly  every  statement 
made,  and  it  is  only  by  gathering  together  and  correlating 
evidence  from  many  sources  that  any  approach  to  real  accuracy 
will  be  made. 

For    purposes   of  convenience  soils   may  be  classified  as 
follows  : — 

(1)  Clays  and  heavy  loams. 

(2)  Medium  loams. 

(3)  Light  loams  and  sand. 

(4)  Chalk. 

(5)  Special  soils,  as  peat. 

Such  a  classification  is  necessary  for  working  purposes,  but  in 
actual  fact  no  hard  and  fast  line  can  be  drawn  between  the 
different  sections.  Clays  and  heavy  loams  merge  imperceptibly 
into  the  medium  soils,and  there  is  no  sharp  dividing  line  between 
medium  loam  and  the  lighter  soils.  Again,  land  that  is 
termed  clay  in  one  part  of  the  country  will  pass  as  loam  else- 
where, the  terminology  depending  to  a  large  extent  upon  the 
general  nature  of  the  soils  in  the  surrounding  district.  Never- 
theless, when  an  investigator  is  constantly  working  on  various 
soils  in  different  districts,  a  recognition  of  the  relative  lightness 
or  heaviness  of  the  land  develops  almost  instinctively,  and 
experience  enables  the  classification  of  the  weeds  according  to 
the  soil  they  occupy  to  be  made  with  a  fair  degree  of  accuracy. 
In  addition  to  determining  the  soil  with  which  a  weed  is 
associated,  it  is  necessary  to  draw  a  distinction  between  the 
frequency  with  which  a  plant  occurs  and  the  amount  of  it  that 
is  present.  A  weed  like  field  forget-me-not  may  be  fre- 
quently found  on  any  soil,  and  yet  it  may  occur  in  such  small 
quantities  that  it  is  often  noted  as  being  scarce  in  the  fields, 
while  it  may  never  be  present  in  such  abundance  as  to  be 
dominant.1  On-the  other  hand,  such  plants  as  field  speedwell, 

1  The  relative  abundance  of  weed  species  in  any  field  is  indicated  by  the 
following  terms  : — 

(1)  Dominant. — When  one  species  is  much  more  abundant  than  any  other. 

(2)  Sub-dominant. — When  a  second  species,  less  plentiful  than  the  dominant 
one,  is  also  more  plentiful  than  the  other  species  of  the  flora. 

(3)  Distributed. — When  a  weed  is  rather  plentiful  over  the  whole  of  a  field, 
but  is  not  relatively  more  abundant  than  other  associated  species. 

(4)  Occasional  or  sparse. — When  occasional  specimens  of  a  weed  are  to  be 
found  here  and  there. 

(5)  Scarce  or  rare. — When  isolated  individuals  occur,  sometimes  only  one  or 
two  specimens  being  found. 


ARABLE  WEEDS.     ASSOCIATION  WITH  SOILS     123 

chickweed,  curled  dock,  and  fat  hen  are  found  on  all  soils  in 
such  abundance  that  they  are  often  dominant.  Again,  a  weed 
may  occur  on  all  soils  but  it  may  be  far  more  abundant  on 
some  types  than  on  others,  as  happens  with  ribwort  plantain 
which  is  occasionally  dominant  on  chalky  soils  and  not  else- 
where, and  black  bindweed  which  is  often  dominant  on  light 
soils  but  not  on  heavier  land.  This  local  dominance  of  ubiq- 
uitous weeds  gives  a  good  indication  of  the  soils  which  are 
really  preferred  by  the  species.  Thus  the  frequency  with 
which  a  weed  occurs  is  not  necessarily  associated  with  its 
abundance.  Naturally  enough  the  weeds  that  are  of  universal 
distribution  are  usually  the  most  frequent  in  occurrence,  as  they 
are  not  limited  by  the  soil  conditions,  and  so  have  a  greater 
choice  of  habitat,  but  on  the  other  hand  plants  that  are 
specially  localised,  as  spurry  and  white  mustard,  are  generally 
far  more  abundant  in  their  particular  situation  than  are  the 
weeds  of  general  distribution.  v 

In  the  following  pages  a  weed  is  said  to — 

(1)  be  characteristic  of  a  soil  when  it  is  usually  frequent  or 
abundant  on  that  soil  but  only  occurs  infrequently  and  in  small 
amounts  on  other  types  of  land. 

(2)  have  a  preference  for  a  particular  soil  if.it  is  more  often 
frequent  or  abundant  on  that  soil  than  on  any  other. 

(3)  be  generally  distributed  if  it  shows  no  preference  for 
one  soil  more  than  another. 

The  chief  arable  weeds  may  be  classified  according  to  their 
association  with  soils,  as  follows : — 

A.  Weeds  of  General  Occurrence. 

(a)  Plants  that  are  equally  distributed  on  all  types  of  soil. 

(b)  Plants    occurring  on  all  soils,  but    less  frequently  on 

heavy  land. 

(c)  Plants  occurring  on  all    soils,  but  less    frequently  on 

chalk. 

B.  Weeds  Specially  Associated  with  Heavy  Land. 

(a)  Plants  characteristic  of  heavy  land   (clay  and    heavy 

loam). 

(b)  Plants  common  on  heavy  land,  but  also  of  general  dis- 

tribution. 

(1)  Plants  which  flourish  equally  well  on  chalk. 

(2)  Plants  which  do  not  occur  so  frequently  on  chalk. 
(a)  With  distinct  preference  for  the  heavier  soils. 
(/?)  Equally  plentiful  on  heavy  and  medium  soils. 


124  WEEDS  OF  FARM  LAND 

C.  Weeds  Characteristic  of  Sand  and  very  Light  Soil  Deficient 

in  Lime. 

D.  Weeds  Associated  with  Chalk, 
(a)  Plants  characteristic  of  chalk. 

(//)  Plants  with    a  definite  preference  for  chalk,  but  also 

occurring  on  all  soils. 
(c)  Plants  with  a  definite  preference  for  light  and  sandy 

soils  as  well  as  for  chalk. 

E.  Weeds  Associated  with  Peat  Soils. 

A.    Weeds  of  General  Occurrence. 

By  far  the  larger  proportion  of  arable  weeds  are  to  be 
found  distributed  over  all  types  of  soil  instead  of  being 
definitely  associated  with  one  or  two  particular  soils.  At  first 
sight  it  looks  as  though  these  weeds  were  absolutely  indifferent 
to  the  nature  of  their  habitat,  but  a  close  numerical  analysis 
of  observations  made  on  their  occurrence  shows  that  there  is  a 
considerable  amount  of  differentiation,  and  that  even  though  a 
weed  be  of  universal  distribution  it  often  has  definite  preferences 
or  mild  dislikes  for  certain  soils.  This  is  shown  both  by  the 
frequency  with  which  a  weed  occurs  on  a  soil  and  by  its 
relative  abundance,  and  the  weed  communities  which  are 
characteristic  of  the  different  habitats  owe  a  great  deal  to 
those  plants  that  are  very  tolerant  and  that  yet  have  their 
preferences  as  to  soil.  The  presence  of  a  quantity  of  the 
universally  distributed  scabious  (S.  arvensis)  on  chalky  land  is 
quite  as  characteristic  as  that  of  wild  mignonette  (Reseda  luted), 
which  is  practically  confined  to  such  situations.  Indeed,  there 
are  so  few  plants  which  are  really  soil  indicators  that  if  it 
were  not  for  the  grouping  into  characteristic  communities  of 
these  weeds  of  general  distribution  it  would  be  difficult  or  im- 
possible to  determine  the  weed  communities  that  are  associated 
with  the  different  soils. 

It  is  gradually  becoming  evident,  however,  that  much  of  the 
"  universal  occurrence"  of  certain  weeds  is  more  apparent  than 
real.  Some  of  the  commonest  weeds,  as  knotgrass  (P.  aviculare), 
show  very  great  difference  in  character — differences  so  great  that 
it  seems  impossible  that  they  are  due  to  mere  local  variations 
brought  about  by  particular  conditions  of  soil  and  climate. 
The  knotgrass  will  vary  from  a  type  consisting  of  very  thin, 
wiry  stems  bearing  tiny  narrow  leaves  hardly  £  inch  long  to 
another  of  a  much  more  succulent  nature,  in  some  cases  with 


ARABLE  WEEDS.     ASSOCIATION  WITH  SOILS      125 

large  broad  leaves  nearly  2  inches  long.  It  is  an  accepted 
fact  that  many  of  these  variations  constitute  true  sub-species, 
but  the  classification  and  differentiation  are  still  so  hazy  and 
uncertain  that  it  has  not  yet  been  practicable  to  make  use  of 
these  "  splits  "  of  species  in  studying  the  weed  flora.  It  is, 
however,  very  probable  that  when  matters  are  cleared  up  more 
it  will  be  found  fhat  some  of  the  main  splits  are  of  very  great 
importance  and  possibly  certain  splits  will  prove  to  be  as 
characteristic  of  different  types  of  soil  as  such  species  as  spurry 
are  of  sand.  Meanwhile  we  must  be  content  to  accept  these 
weeds  as  occurring  on  all  soils,  remembering  that  we  may  be 
dealing  with  a  variety  of  types  instead  of  with  a  single  one. 

The  account  of  the  weeds  of  general  occurrence  may 
conveniently  be  broken  up  into  sections  according  to  the 
classes  of  soils  that  are  more  or  less  particularly  favoured. 
The  division  is  made  with  due  reserve,  and  is  purely  artificial 
in  nature,  because  its  truth  and  convincingness  will  vary  ac- 
cording to  the  districts,  soils,  and  cultural  conditions  with 
which  the  reader  is  acquainted.  Weeds  that  are  classified 
into  one  section  on  a  general  analysis  may  belong  to  another 
section  for  a  particular  area,  so  it  must  be  borne  in  mind  that 
the  classification  is  the  result  of  observations  made  on  many 
hundreds  of  fields  scattered  over  the  country,  and  so  may  give 
a  fairly  true  general  picture. 

(#)  Plants  that  are  Equally  Distributed  on  all  Types  of  Soil. 
— A  certain  number  of  weeds  appear  to  be  truly  ubiquitous, 
occurring  on  any  and  every  soil  without  preference.  Naturally 
enough  some  of  the  very  commonest  farm  pests  come  under 
this  heading,  as  the  faculty  of  being  able  to  live  happily  under 
any  circumstances  favours  the  spread  and  persistence  of  these 
plants  to  an  exceptional  degree.  Some  of  them  are  very 
widely  spread,  as  is  shown  by  the  following  table  which  gives 
the  number  of  times  some  of  the  commonest  weeds  were 
noted  during  the  investigation,  together  with  their  percentage 
of  frequency x  on  the  various  classes  of  soils  : — 

1  Percentage  of  frequency  =  number  of  times  seen  per  100  fields. 


126 


WEEDS  OF  FARM  LAND 


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ARABLE  WEEDS.     ASSOCIATION  WITH  SOILS      127 

The  table  also  shows  how  persistently  some  of  the  worst 
weeds,  as  thistle,  knotgrass,  black  bindweed,  and  fat  hen, 
maintain  their  hold  upon  the  ground  in  spite  of  the  strenuous 
efforts  of  the  farmer  to  eradicate  them.  The  creeping 
thistle  masters  the  situation  more  frequently  than  any  other 
weed.  No  matter  what  the  soil  nor  how  carefully  the  land  is 
farmed  it  is  almost  impcJssible  to  get  rid  of  it,  and  it  takes 
advantage  of  every  opportunity  to  spread  more  and  more.  It 
occurred  on  73  per  cent,  of  the  fields  examined,  and  in  125  of 
these,  i.e.  II  per  cent,  it  was  the  chief  and  dominant  weed, 
holding  the  worst  record  of  all  weeds  in  this  respect. 

The  curled  dock  (Rumex  crispus)  may  be  dominant  on 
any  soil,  and  it  would  be  rampant  everywhere  if  it  were  left 
alone,  but  so  much  time  and  labour  has  been  spent  on  its 
eradication  that  the  presence  of  too  many  docks  in  normal 
times  is  a  sign  of  bad  farming  and  neglect.  It  is  possible  to 
make  a  clearance  by  persistent  effort.  Fat  hen  and  chickweed 
are  often  dominant  on  various  soils,  but  field  speedwell, 
groundsel,  and  shepherd's  purse  less  frequently.  Most  of 
the  other  weeds  show  some  preference  in  their  dominance. 
Black  bindweed  is  frequently  the  chief  weed  on  the  lighter 
soils,  but  was  never  seen  dominant  on  clay  or  chalk,  whereas 
its  close  relative  knotgrass  is  dominant  on  all  types  of 
soil,  heavy  or  light,  chalky  or  non-calcareous  though  it 
dominates  rather  more  frequently  on  the  lighter  than  on  the 
heavier  soils.  Ribwort  plantain  and  shepherd's  needle  are 
seldom  abundant,  but  very  occasionally  they  will  dominate  on 
chalky  soil.  The  shepherd's  needle  is  curiously  local  in  its 
distribution.  In  Bedfordshire,  Nottinghamshire  and  Derby- 
shire it  seems  to  be  absent  from  chalk,  and  behaves  practically 
as  a  calcifuge.  In  Norfolk  it  was  never  seen  on  chalk  and  only 
occasionally  on  chalky  loam,  but  in  the  West  Country  it  is 
most  prevalent  on  chalk  and  on  other  soils  of  very  calcareous 
nature,  so  that  in  that  area  it  is  chalk-loving  instead  of  calci- 
fuge. This  is  probably  one  of  the  cases  in  which  competition " 
and  local  conditions  have  far  more  to  do  with  distribution 
than  the  nature  of  the  soil,  though  it  is  not  very  usual  for  such 
a  complete  inversion  of  the  habitats  to  take  place. 

Bent  grass  (Agrostis  spp.),  commonly  known  as  twitch  or 
couch,  causes  much  trouble  in  places.  It  may  be  dominant 
on  any  type  of  soil,  and  indeed  in  the  frequency  with  which 
it  is  the  chief  weed  on  a  field  it  takes  third  place.  On  the 
lighter  soils  it  is  frequently  scuffled  out  and  burnt  in  heaps, 


128 


WEEDS  OF  FARM  LAND 


but  on  heavier  land  it  is  far  more  difficult  to  eradicate,  as  the 
creeping  stems  are  very  full  of  vitality  and  each  small  broken 
piece  is  capable  of  starting  a  new  plant  on  its  own  account. 

Jn  addition  to  these  ubiquitous  weeds  which  occur  in  such 
quantities  as  to  make  them  an  important  economic  factor 
there  are  a  few  others  which  are  more  or  less  uncommon  but 
which  are  equally  cosmopolitan  in  habitat.  Petty  spurge  and 
field  forget-me-not  are  widespread  but  never  very  plentiful. 
The  pale  red  poppy  (P.  dubium]  occurs  more  frequently  than 
is  recognised  as  it  is  probably  often  confused  with  the  common 
red  poppy. 

Silverweed  (Potetttilla  anserine?)  although  it  occurred  in 
IO  per  cent  of  the  fields  examined  was  frequently  in  such 
small  amounts  as  to  be  scarce.  Only  on  three  occasions  was 
it  dominant  and  in  each  case  this  was  on  chalky  land.  It  is 
quite  probable  that  this  weed  in  spite  of  its  general  distribution 
has  some  preference  for  calcareous  soil.  Creeping  buttercup, 
mouse-ear  chickweed,  field  madder  and  wild  radish  are  speci- 
ally characterised  by  the  number  of  times  that  they  are  scarce 
when  they  do  occur,  as  is  shown  by  the  following  table : — 


No.  of  Times 

No.  of  Times 

No.  of  Times 

Per  Cent,  of 

Seen. 

Dominant. 

Scarce. 

Times  Scarce. 

Creeping  buttercup    . 

149 

2 

20 

13 

Mouse-ear  chickweed 

83 

— 

15 

18 

Field  madder     . 

85 

— 

22 

26 

Wild  radish       . 

41 

2 

22 

54 

In  addition  to  the  weeds  noted  above,  a  number  of  others 
occur  with  less  frequency;  in  the  course  of  the  investigation 
they  were  seen  but  twenty  times  or  less  in  arable  fields.  The 
indications  are,  however,  that  most  of  these  plants  are  com- 
paratively indifferent  as  to  soil,  as  they  were  found  on  all 
types  of  land. 


*  Achillea  millefolium 
j&thusa  cynapium  . 

*  Bellis  perennis 
Brassica  campestris 
Cirsium  lanceolatum 
Caucalis  nodosa 

*  Chrysanthemum  leucanthemum 

*  Lychnis  dioica         ,         . 


Yarrow. 
Fool's  parsley. 
Daisy. 

Field  cabbage. 
Spear  thistle. 
Knotted  caucalis. 
Dog  daisy. 
Red  campion. 


ARABLE  WEEDS.     ASSOCIATION  WITH  SOILS     129 


Nepeta  glechoma 
Potentilla  reptans    . 

*  Prunella  vulgaris  . 

*  Ranunculus  bulbosus 

*  Sisymbrium  officinale 
Urtica  dioica 


Ground  ivy. 
Cinquefoil. 
Selfheal. 

Bulbous  buttercup. 
Hedge  mustard. 
Stinging  nettle. 


The   weeds   marked  *  were  very  often   scarce,  and  it  is. 
noticeable   that   they  are  all  characteristic   of  grass-lands   or 
hedges,  and  are  not  commonly  associated  with  arable  land. 
In  no  single  case  did  any  weed  in  this  list  attain  a  position  of 
dominance. 

Thalecress  (Arabis  thaliana)  may  perhaps  be  included 
here  though  it  was  only  seen  three  times,  on  three  different 
types  of  soil,  in  Bedfordshire.  Arable  land  is  a  very  unusual 
habitat  for  this  species,  it  being  a  frequenter  of  old  walls  and 
waste  stony  places  and  not  usually  appearing  on  cultivated  soil. 

(b)  Plants  Occurring  on  all  Soils,  but  less  Frequently  on 
Heavy  Land. — A  small  number  of  the  weeds  that  are  of  general 
distribution  are  much  less  common  on  heavy  loams  and  clays 
than  they  are  on  the  lighter  soils,  on  which  as  a  rule  they 
are  fairly  evenly  distributed.  The  number  of  species  that  come 
under  this  heading  is  very  restricted,  as  usually  the  weeds  that 
are  scarce  on  the  heavy  land  show  some  definite  preference  for 
a  particular  type  of  soil,  such  as  sand  or  chalk,  which  does  not 
occur  in  this  case. 


TABLE  II.— WEEDS  OF  GENERAL  OCCURRENCE,  BUT  LESS  FREQUENT 

ON  HEAVY  LAND. 


No. 

Percentage  of  Frequency  (=  Number  of  Times 
Seen  per  100  Fields). 

Latin  Name. 

English  Name. 

of 

Times 

Seen. 

All 
Soils. 

Heavy. 

Medium. 

Light. 

Chalk. 

Peat. 

Anthemis  arvensis 

Corn  chamomile     . 

^8 

3 

'7 

1*5 

4 

6 

7 

Arenaria  serpyllifolia 

Sandwort 

no 

10 

2 

12 

II 

16 

Euphorbia  helioscopia 
Geranium  molle 

Sun  spurge 
Soft  crane's-bill 

72 
84 

6 

7"> 

3 
2-7 

II 
13 

4'5 
7 

13 
II 

— 

Papaver  rhoeas 

Common  red  poppy 

367 

33 

16 

38 

3« 

34 

~~ 

The  common  red  poppy  (Papaver  rhoeas}  is  so  very  wide- 
spread and  abundant  that  in  some  districts  it  is  one  of  the 
most  difficult  weeds  to  fight.  It  is  popularly  believed  to 
be  peculiarly  a  weed  of  sand  and  very  light  soils,  but  close 

9 


1 3o  WEEDS  OF  FARM  LAND 

investigation  has  shown  that  it  is  really  far  more  cosmopolitan. 
It  is  as  common  on  medium  loams  as  on  light  loams  and 
sand,  and  it  is  also  seen  quite  often  on  the  heavy  loams  and 
clays.  In  fact  the  proportion  of  the  number  of  occurrences 
in  these  situations  reaches  50  per  cent,  of  those  on  all  the 
other  soils.  Poppies  are  frequently  dominant — in  367  occur- 
rences they  took  first  place  93  times — but  they  are  never  domin- 
ant on  clay,  and  but  rarely  on  heavy  loam.  Here  again  the 
popular  mind  is  astray,  as  the  records  of  dominance  are  nearly 
as  frequent  in  proportion  from  medium  loam  as  they  are  from 
sand  and  sandy  soils,  though  light  loams  have  a  lead  in  this 
respect.  Equally  striking  is  the  frequency  with  which  the 
weed  is  scarce — 69  times  in  the  367  observations.  Naturally 
enough,  this  scarcity  is  more  marked  on  the  clays  and  heavy 
loam,  but  it  is  also  very  noticeable  on  all  the  lighter  types  of 
soil. 

Sand  wort  (Arenaria  serpyllifolid]  is  apparently  localised  in 
its  distribution.  It  was  seen  103  times  in  Norfolk,  but  only 
seven  times  altogether  in  the  other  districts  visited.  It  is 
quite  possible  that  it  may  occasionally  have  been  overlooked, 
as  sometimes  it  closely  resembles  small  forms  of  Stellaria 
media,  but  it  is  improbable  that  it  would  have  escaped  detec- 
tion to  any  serious  extent.  It  has  a  much  stronger  dislike  of 
heavy  soils  than  has  Papaver  rhceas,  and  also  it  shows  a  cer- 
tain preference  for  chalk.  Sandwort  is  rarely  dominant  and 
rarely  scarce  ;  it  avoids  extremes  and  simply  takes  its  place 
as  an  inconspicuous  member  of  the  weed  flora,  seldom  playing 
any  striking  part. 

Soft  crane's-bill  (Geranium  molle]  and  sun  spurge  (Euphorbia 
helioscopid]  resemble  one  another  in  that  in  addition  to  being 
scarce  on  heavy  land  they  are  also  less  prevalent  on  the  lighter 
soils,  including  sandy  and  light  loams  and  sand.  Soft  crane's- 
bill  was  once  seen  dominant  on  sand,  and  is  rather  often  scarce 
in  quantity,  but  the  sun  spurge  never  dominates  and  is  more 
usually  scarce  on  any  kind  of  soil.  The  latter  plant  is  a  most 
insignificant  member  of  the  weed  community,  and  were  it  not 
that  it  thrusts  itself  upon  one's  notice  by  its  peculiar  colour 
and  conformation,  would  often  run  great  risk  of  being  over- 
looked. 

Corn  chamomile  (Anthemis  arvensis}  is  less  common  than 
some  of  the  other  mayweeds,  and  is  hardly  found  at  all  in 
some  districts.  It  very  occasionally  dominates  on  light  or 
chalky  soils  and  is  often  scarce  on  any  soil. 


ARABLE  WEEDS.     ASSOCIATION  WITH  SOILS      131 

(c)  Plants  Occurring  on  all  Soils,  but  less  Frequently  on 
Chalk. — The  weeds  in  this  category  show  a  regular  gradation 
of  frequency. 

(1)  Plants  that  are  merely  less  common  on  chalky  soils, 
such  as  Veronica  hedercefolia  and  Veronica  arvensis. 

(2)  Plants  that  are  so  much  less  common  on  chalk  that  a 
dislike  of  such  soil  is  suggested,  as  Alchemilla  arvensis,  Lamium 
purpureum^  Matricaria  chamomilla,  Matricaria  inodora^  and  Poa 
annua. 

(3)  Plants  which  are  so  infrequent  on  chalk  that  a  dislike 
of  calcareous  soil  is  evident,  as  Papaver  argemone,  Polygonum 
persecaria^  Rumex  obtusifolius. 


TABLE  III.— WEEDS  OCCURRING  ON  ALL  SOILS,  BUT  LESS  FRE- 
QUENTLY ON  CHALK. 


.Percentage  of  Frequency  (—  Number  of 

c 

Times  Seen  per  100  Fields). 

Latin  Name. 

English  Name. 

y 

£ 

^ 

a 

.j 

d 

i 

I 

.2 

"O 

J3 
60 

"3 

3 

3 

£ 

x 

3 

o 

a, 

Veronica  arvensis 

Wall  speedwell 

80 

7 

8 

8 

8 

4 

Veronica  hedercefolia  . 

Ivy-leaved  speedwell  . 

206 

18 

22 

15 

21 

9 

— 

Alchemilla  arvensis 

Lady's  mantle    . 

96 

8-6 

3'5 

13 

II 

3 



Lamium  purpureum 

Red  dead-nettle. 

39 

3'5 

3*5 

6 

3 

'7 



Matricaria  chamomilla 

Wild  chamomile 

29 

3 

3'5 

i 

3 

7 

— 

Matricaria  inodora 

Scentless  mayweed    . 

181 

16 

16 

18 

19 

4 

15 

Poa  annua   . 

Annual  meadow-grass 

195 

*7 

17 

25 

18 

4 

23 

Papaver  argemone 

Pale  poppy 

17 

1-5 

1-5 

ii 

1-6 

— 

— 

Polygonum  persecaria  . 

Willow-weed 

132 

12 

2-6 

12 

13 

•6 

90 

Rumex  obtusifolius 

Broad  dock 

4° 

3-6 

3'5 

4 

4'5 

— 

(i)  Ivy-leaved  speedwell  (Veronica  hedercefolia}  is  of  fre- 
quent occurrence  and  is  often  dominant.  The  plant  is  of  a 
very  early  and  ephemeral  habit,  and  as  soon  as  growth  is 
completed  it  ripens  its  seeds  and  dies  off  rapidly,  so  that  in 
many  cases  by  the  end  of  June  few  traces  of  an  abundance  of 
plants  are  to  be  seen.  Consequently,  it  may  easily  happen 
that  if  fields  are  examined  late  in  the  season  the  speedwell 
may  be  missed  in  areas  in  which  it  dominates  at  an  earlier  date. 
It  seems  to  be  equally  dominant  on  all  types  of  soil,  as  even 
on  chalk  it  maintains  its  position  in  this  respect,  although  the 
plant  is  so  much  less  frequently  seen  in  this  situation. 

Wall  speedwell  (Veronica  arvensis}  is  much  less  common 

9* 


132  WEEDS  OF  FARM  LAND 

than  its  ally  and  usually  occurs  in  very  small  quantities,  never 
being  present  in  any  abundance. 

(2)  Lady's  mantle  (Alchemilla  arvensis)  is  uncommon  both 
on  chalky  and  heavy  land,  and  possibly  is  the  more  intoler- 
ant of  the  latter.  When  it  does  occur  on  clay  or  heavy 
loam  it  is  usually  scarce,  but  on  calcareous  soil  it  'is  dis- 
tributed more  evenly,  and  is  often  present  in  fair  amount. 
Very  occasionally  it  is  dominant  or  sub-dominant  on  very  light 
soils  or  sand,  but  as  a  general  rule  it  is  insignificant  and  in- 
conspicuous. 

Red  dead-nettle  (Lamium  purpureum)  always  has  the  air  of 
being  an  intruder  among  arable  weeds,  as  it  never  seems  fully 
at  home  in  such  surroundings.  Its  preference  is  for  medium 
loam,  and  it  is  very  rare  on  chalk  ;  so  rare  that  it  may  almost 
be  considered  as  absent.  This  dead-nettle  is  never  dominant, 
and  never  abundant,  but  is  often  present  in  mere  traces. 

The  mayweeds  (Matricaria  inodora  and  Matricaria  chamo- 
milld]  resemble  one  another  in  distribution,  but  the  former  is 
much  the  more  common.  The  scentless  mayweed  (M.  inodora) 
is  frequently  dominant  or  sub-dominant  on  all  soils  save  chalk, 
and  it  is  probable  that  it  would  dominate  still  more  often  if  it 
were  not  for  its  habit  of  clinging  to  the  edges  and  open  spaces 
of  the  corn  fields,  and  of  refusing  to  flourish  among  the  corn, 
even  in  places  that  are  particularly  favourable  for  its  growth. 
This  same  habit  also  accounts  for  the  frequency  with  which 
the  weed  seems  to  be  scarce,  as  if  the  crop  competition  is  extra 
strong  the  mayweed  gives  up  the  struggle  at  the  outset  and 
entirely  fails  to  assert  itself. 

Wild  chamomile  (Matricaria  chamomilld)  is  very  rarely 
found  on  soil  of  any  calcareous  type,  and  probably  the  plant 
should  be  classified  amongst  those  in  section  (3)  which  are  in- 
tolerant of  chalk.  Although  this  mayweed  is  so  infrequent  it 
is  sometimes  dominant,  usually  on  sandy  soil,  and  occasionally 
on  clay. 

Annual  meadow-grass  (Poa  annud)  is  one  of  the  very  few 
grasses  that  may  fairly  be  regarded  as  a  true  arable  weed  and 
not  as  a  mere  survival  from  a  previous  "seeds"  crop.  It  is 
frequent  on  all  soils  except  those  of  calcareous  nature  and  is 
often  present  in  some  quantity,  though  it  is  not  often  domi- 
nant. Very  occasionally,  however,  it  is  so  plentiful  that  it 
carpets  the  ground  and  even  receives  the  local  name  of  twitch 
(this  occurred  at  Gedling  in  Notts),  but  such  prevalence  is  un- 
usual, the  weed  being  easily  kept  down  by  careful  cultivation, 


ARABLE  WEEDS.     ASSOCIATION  WITH  SOILS     133 

(3)  Willow-weed  (Polygonum persecaria)  stands  apart  from 
all  other  weeds  in  its  habits  and  habitats.  It  is  most  intoler- 
ant of  chalk,  but  otherwise  seems  indifferent  to  the  nature  of 
the  soil.  Sometimes  it  behaves  like  other  weeds  and  is  spread 
more  or  less  evenly  over  the  fields,  or  is  segregated  in  areas 
that  are  determined  by  definite  and  marked  local  conditions. 
More  usually,  however,  its  distribution  is  sporadic.  It  occurs 
here  and  there  in  spots,'  sometimes  at  the  bottom  of  a  field, 
where  the  soil  is  moister,  sometimes  towards  the  top,  where 
no  obvious  difference  in  water  content  is  evident.  It  is  abun- 
dant and  usually  dominant  on  peaty  soils  and  grows  happily 
in  parts  of  fields  that  are  often  waterlogged  or  are  churned  up 
into  thick  mud  by  the  farm  traffic.  When  the  plant  occurs 
high  and  dry  towards  the  top  of  a  field,  inquiry  will  often  elicit 
the  information  that  a  spring  emerges  near  by,  or  that  at  some 
periods  of  the  year  those  spots  are  extra  damp  from  some 
source  of  underground  water.  Careful  consideration  leads  to 
the  conclusion  that  soil  plays  but  a  small  part  in  determining 
the  distribution  of  willow-weed,  but  that  a  plentiful  supply  of 
underground  water  is  essential  if  the  plant  is  to  flourish. 
Chalky  soils  are  thoroughly  well  drained,  and  rarely  have 
sodden  spots,  so  the  absence  of  willow-weed  from  these  situa- 
tions may  be  due  either  to  chalk  intolerance  or  to  a  deficient 
water  supply.  The  weed  is  frequent  enough  on  sand,  and  is 
even  sometimes  dominant  there,  but  sandy  soils  often  have 
damp  soggy  spots  in  which  the  plant  can  flourish,  or  the  water 
table  may  be  sufficiently  near  the  surface  to  enable  the  roots 
to  travel  down  to  reach  abundant  moisture. 

On  the  heavy  clay  fields  in  part  of  Somerset,  which  are 
low-lying  and  near  the  moors,  willow-weed  flourishes  well  and 
spreads  uniformly  over  the  whole  area,  as  the  necessary  con- 
ditions of  moisture  are  fulfilled  everywhere,  and  not  only  in 
isolated  spots. 

Pale  poppy  (Papaver  argemone)  is  seldom  seen,  either  be- 
cause it  really  does  not  occur,  or  because  it  is  present  in  such 
small  quantities  that  it  is  overlooked  or  confused  with  other 
larger  species  of  poppy.  It  occurs  anywhere  except  on  chalky 
soils,  but  is  often  scarce. 

Broad  dock  (Rumex  obiusifolius)  must  be  regarded  as  an 
interloper  among  arable  weeds.  It  seems  to  object  strongly 
to  chalk  or  else  it  so  happened  that  it  had  been  cultivated  out 
of  existence  in  every  field  visited  during  the  course  of  the  in- 
vestigation. The  plant  is  essentially  a  weed  of  waste  places, 


134 


WEEDS  OF  FARM  LAND 


and  even  when  it  flourishes  well  in  the  corner  of  the  fields, 
hedgerows,  etc.,  it  rarely  migrates  among  the  crops.  It  is, 
however,  difficult  to  pass  judgment  in  this  respect,  as  the  weed 
is  so  big  and  so  obnoxious  that  when  it  does  appear  it  is  usually 
eliminated  with  the  greatest  possible  speed  by  a  good  farmer. 

B.    Weeds  Specially  Associated  with  Heavy  Land. 

(a)  Plants  Characteristic  of  Heavy  Land  (Clay  and  Heavy 
Lo.ims). — There  is  no  weed  so  exclusively  associated  with  clay 
and  heavy  loam  that  it  may  be  described  as  "  symptomatic," 
but  a  very  few  are  so  much  more  often  seen  on  such. soils  than 
on  any  other  that  perhaps  they  may  fairly  be  called  "charac- 
teristic ".  None  of  the  five  weeds  classified  thus  are  of  frequent 
occurrence,  as  naturally  the  close  association  of  a  plant  with 
a  particular  type  of  soil  considerably  limits  its  distribution. 

TABLE  IV.— WEEDS  CHARACTERISTIC  OF  HEAVY  LAND  (CLAY  AND 

HEAVY  LOAMS). 


Percentage  of  Frequency  (=  Number 

Total 

of  limes  Seen  per  100  Fields). 

Latin  Name. 

English  Name. 

Occurrence 
on  all 

Soils. 

All 
Soils. 

Clay. 

Heavy 
Loam. 

Chalk. 

Other 
Soils. 

Anthemis  cotula 

Stinking  mayweed   . 

16 

1*4 

4 

I 

•6 

I 

Geranium  dissectum 

Cut-leaved  geranium 

19 

17 

4 

4 

— 

1*2 

Plantago  media 

Hoary  plantain 

18 

1-6 

7 

i 

— 

7 

Ranunculus  arvensis 

Corn  buttercup 

49 

4 

14 

6 

3 

2 

Alopecurus  agrestis  . 

Black  bent 

54 

5 

14 

10 

5 

2 

Stinking  mayweed  (Anthemis  cotula),  although  so  seldom 
seen,  is  apparently  closely  associated  with  clay,  on  which  it 
is  even  sometimes  dominant.  When  it  does  occur  on  other 
soils  very  little  of  it  is  present  as  a  rule,  and  it  is  often  in 
such  mere  traces  as  to  be  scarce. 

Cut-leaved  geranium  (Geranium  dissectum}  is  equally  at 
home  on  clay  and  heavy  loam,  but  curiously  enough  it  has 
been  seen  to  reach  a  position  of  sub-dominance  on  a  light  loam, 
at  Flitwick  (Beds).  It  does  not  seem  to  occur  on  chalk. 

Hoary  plantain  (Plantago  media)  has  a  most  decided  pre- 
ference for  clay  soil,  and  it  is  usually  regarded  by  farmers  as 
a  sign  that  the  land  is  in  good  heart.  It  is  never  present  in 
any  quantity,  and  is  seldom  seen  on  arable  land. 


ARABLE  WEEDS.     ASSOCIATION  WITH  SOILS      135 

Corn  buttercup  {Ranunculus  arvensis),  though  very  local 
in  occurrence,  is  sometimes  a  bad  weed  on  heavy  wheat 
land,  and  the  heavier  the  land  the  more  likely  is  the  plant  to 
cause  trouble.  It  is  sometimes  dominant,  and  the  presence  of 
the  seeds  in  the  corn  tends  to  depreciate  the  value  of  the 
wheat  considerably  as  so  much  more  cleaning  is  necessitated. 
The  weed  is  far  more  characteristic  of  clay  and  heavy  loam 
than  appears  from  the  table,  for  although  it  occurs  on  the 
other  soils  as  indicated  it  is  usually  so  scarce  that  only  close 
observation  reveals  its  presence.  Probably  in  many  of  these 
cases  it  has  simply  sprung  from  stray  seeds  introduced  when 
the  crop  was  sown. 

The  inclusion  of  black  bent  (Alopecurus  agrestis)  in  this 
list  may  perhaps  be  criticised,  as  it  occurs  quite  frequently  on 
other  soils  and  is  also  dominant  on  them.  Nevertheless,  the 
preference  for  clay  and  heavy  loam  is  so  marked  that  a  point 
may  be  stretched  to  include  it  among  the  characteristic  heavy 
land  weeds.  Black  bent  is  capable  of  doing  much  damage 
among  corn  crops  but  happily  does  not  usually  occur  in  any 
quantity,  its  habit  being  such  that  ordinary  methods  of  rotation 
farming  keep  it  in  check.  Occasionally,  though,  it  has  been 
seen  dominant  on  clay,  chalk,  and  medium  loam,  and,  when  it 
does  occur,  is  not  often  scarce  but  usually  present  in  ap- 
preciable amount. 

(b)  Plants  Common  on  Heavy  Land,  but  also  of  General 
Distribution. — Several  of  the  most  common  and  abundant 
weeds  are  found  distributed  over  every  type  of  soil,  but  never- 
theless they  occur  more  frequently  and  more  plentifully  on 
the  heavier  soils.  The  frequency  with  which  the  weeds  in 
this  class  occur  is  in  striking  contrast  with  the  scanty  distribu- 
tion of  those  pla-nts  which  are  really  characteristic  of  the  heavy 
soils.  These  weeds  may  be  divided  into  two  distinct  sections. 

(1)  Plants  which  flourish  equally  well  on  chalk. 

(2)  Plants  which  do  not  occur  so  plentifully  on  chalk. 
(a)  With  distinct  preference  for  the  heavier  soiU 
(£)  Equally  plentiful  on  heavy  and  medium  soils. 

In  both  cases  the  lighter  loams  and  sand  afford  less  con- 
genial habitats. 


i36 


WEEDS  OF  FARM  LAND 


TABLE  V.— WEEDS  COMMON  ON  HEAVY  LAND,  BUT  ALSO  OF  GENERAL 

DISTRIBUTION. 


Percentage  of  Frequency  (=  Number  of 

e 

H  C 

Times  Seen  per  100  Fields). 

Latin  Name. 

English  Name. 

Jj    <1J 

0$ 

g 

>, 

E 

0 

SB 

1 

=5 
< 

1 

P 

1 

4 
3 

5 

J3 

u 

"rt 
1 

I.  FLOURISH  EQUALLY  WELL  ON  CHALK. 

Convolvulus  arvensis  . 

Bindweed  . 

599 

54 

65 

70 

42 

60 



Plantago  major  . 

Greater  plantain 

20  S 

19 

23 

23 

14 

21 



Senebiera  coronopus    . 

Swine  cress 

24 

2    . 

3'5 

2'6 

i 

3*3 



Sonchus  arvensis 

Corn  sow-thistle 

296 

27 

42 

28 

16 

36 

7 

2.  OCCUR  LESS  FREQUENTLY  ON  CHALK. 

(a)  Distinct  Preference  for  the  Heavier  Soils. 

Agropyron  rep  ens 
Brassica  sinapis  . 

Couch-grass 
Charlock    . 

167 
383 

15 

34 

24 
53 

15 
34 

13 
23 

7 
42 

7 
7 

Euphorbia  exigua 

Dwarf  spurge     . 

118 

ii 

22 

14 

3 

J3 

Galium  aparine  . 

Goosegrass 

278 

25 

43 

29 

*3 

30 

15 

Tussilago  farfara 

Coltsfoot    . 

226 

20 

40 

27 

10 

13 

b)  Equally  Plentiful  on  Heavy  and  Medium 

Soils. 

Atriplex  patula  . 
Equisetum  arvense 

Orache 
Horsetail  . 

167 
268 

15 
24 

28 

33 

28 
34 

7 

20 

8 

*5 
15 

Lapsana  communis     . 

Nipplewort 

37 

3'4 

5 

5 

2 

2-6 

Mentha  arvensis 

Corn  mint 

158 

H 

21 

J9 

II 

6 



Veronica  tournefortii  . 

Large  field  speedwell 

290 

29 

37 

37 

21 

12 

— 

( I )  Plants  which  Flourish  Equally    Well  on  Chalk. 

Corn  sow-thistle  (Sonchus  arvensis}  has  a  decided  liking 
for  heavy  soils,  but  is  nearly  as  common  on  calcareous  land. 
In  these  two  habitats  it  is  more  often  dominant  than  else- 
where. Considering  the  frequency  with  which  the  weed 
occurs  it  does  not  often  take  the  first  place,  but  this  may  partly 
be  due  to  the  fact  that  it  is  fond  of  growing  among  cereal 
crops  and  so  is  liable  to  be  pulled  up,  being  a  very  conspicu- 
ous plant,  especially  when  in  flower. 

Greater  plantain  (Plantago  major]  has  much  the  same 
distribution  as  the  corn  sow-thistle,  except  that  it  is  more 
often  seen  on  medium  soils.  Although  it  is  so  common  it  is 
rarely  present  in  any  quantity,  and  in  all  districts  investigated 
it  was  only  once  seen  dominant  on  arable  land,  on  clay. 


ARABLE  WEEDS.     ASSOCIATION  WITH  SOILS      137 

This  weed  is  more  frequent  on  grass-land  than  on  ploughed 
land. 

Swine  cress  (Senebiera  coronopus]  is  a  characteristic  little 
plant,  which  is  not  very  often  noticed.  It  often  congregates 
near  the  gateways  of  fields,  in  the  cart  ruts,  instead  of  scatter- 
ing evenly  over  the  fields.  It  is  hardly  ever  dominant  or 
present  in  great  quantity,  and  is  rarely  seen  on  any  of  the 
lighter  soils. 

Bindweed  (Convolvulus  arvensis]  is  one  of  the  commonest 
of  all  weeds,  so  common  that  it  is  rather  difficult  to  say  that  it 
has  any  real  preference  as  to  soil.  It  seems  evident,  however, 
that  it  is  less  happy  on  the  lighter  types  of  soil.  This  is 
shown  by  the  frequency  with  which  the  weed  occurs  in  the 
different  habitats  and  also  by  the  number  of  times  it  pre- 
dominates on  the  various  soils.  It  is  very  often  dominant  or 
sub-dominant  on  clay,  heavy  and  medium  loam,  and  fairly 
often  so  on  chalk,  whereas  on  the  light  sandy  soils  it  is  less 
frequently  dominant  and  more  often  scarce.  The  abundance 
of  this  weed  may  be  gauged  by  the  fact  that  in  one  occurrence 
out  of  every  five  it  is  either  dominant  or  sub-dominant, 
usually  the  former.  This  is  largely  due  to  its  habit  of  growth, 
as  the  long  creeping  underground  parts  defy  all  efforts  to  clear 
them  out,  especially  on  the  heavy  land,  and  also  the  aerial 
stems  cling  so»closely  to  the  crops  among  which  they  scramble 
that  when  once  growth  has  fairly  started  it  is  almost  impossible 
to  remove  the  weed  without  seriously  damaging  the  crop. 

(2)  Plants  which  do  not  Occur  so  Frequently  on  Chalk. 

(a)    With  Distinct  Preference  for  the  Heavier  Soils. 

Coltsfoot  (Tussilago farfard)  expresses  a  most  decided  pre- 
ference for  heavy  soils.  The  heavier  the  soil,  the  more  likely 
is  coltsfoot  to  be  present,  and  as  the  soil  gets  lighter,  so  does 
the  percentage  of  frequency  of  this  weed  decrease.  Never- 
theless, it  may  be  dominant  on  any  type  of  soil,  clay, 
medium  loam,  light  loam,  sand,  chalk,  or  gravel.  Considering 
the  frequency  with  which  the  plant  occurs  it  is  not  very  often 
dominant,  but  this  may  be  largely  due  to  the  special  attention 
that  farmers  pay  to  its  eradication.  This  same  fact  may  also 
tend  to  decrease  the  frequency  with  which  it  is  seen  on  the 
lighter  soils,  and  to  emphasise  its  universal  occurrence  on 
heavy  land.  The  underground  parts  penetrate  the  soil  so 
deeply  that  it  is  exceedingly  difficult  to  remove  them  effectively 
from  heavy  soil  by  any  of  the  usual  methods  of  cultivation, 


138  WEEDS  OF  FARM  LAND 

but  on  sand  and  light  loam  a  better  clearance  can  be  effected. 
It  is  often  said  that  the  presence  of  coltsfoot  indicates  an 
easily  available  supply  of  underground  water,  or  a  high  water 
table,  but  definite  confirmation  of  this  statement  is  wanting 
The  plant  is  often  one  of  the  first  to  colonise  newly  made 
dumps,  railway  embankments  and  similar  "made"  soils  in 
which  the  water  supply  tends  to  be  deficient  rather  than 
liberal  and  in  which  the  water  table  or  available  underground 
water  lies  at  a  considerable  distance  below  the  surface.  It  also 
comes  in  when  the  nitrogen  content  of  the  soil  is  reduced,  as 
on  the  unmanured  plot  and  that  receiving  minerals  only  on  the 
Broadbalk  field  at  Rothamsted. 

Goosegrass  (Galium  aparine}  is  very  widespread,  but 
shows  as  strong  a  preference  for  heavy  land  as  coltsfoot  does. 
As  an  arable  weed,  however,  it  is  less  plentiful  in  quantity 
and  is  often  scarce  on  all  kinds  of  soil,  especially  light  land, 
though  it  usually  occurs  in  appreciable  quantity  on  chalk.  It 
is  seldom  dominant  in  comparison  with  its  frequency  of  oc- 
currence, but  this  dominance  is  distributed  over  all  soils  and  is 
not  confined  to  heavy  land. 

Couch-grass  (Agropyron  repens)  is  regarded  in  many  districts 
as  one  of  the  most  pestilential  of  weeds.  Every  small  portion 
of  its  rhizome  is  capable  of  originating  a  new  plant,  and  even 
with  the  most  careful  cultivation  it  is  difficult  to  avoid 
scattering  the  pieces  broadcast.  Consequently,  couch-grass  is 
very  often  dominant,  on  any  type  of  soil,  although  in  its  occur- 
rence it  seems  to  show  a  definite  preference  for  heavy  land. 
It  is  quite  possible  that  this  preference  is  not  a  true  one,  and 
this  is  supported  by  the  frequent  dominance  on  sand.  On 
light  soil  it  is  comparatively  easy  to  scuffle  out  the  creep- 
ing rhizomes  without  breaking  them,  and  so  destroy  them 
wholesale.  This  cannot  be  done  on  heavy  land,  as  every 
attempt  at  removal  breaks  the  rhizome  and  leaves  innumer- 
able fresh  starting-points  for  the  weed  in  the  soil.  Conse- 
quently it  may  well  be  that  couch-grass  is  in  reality  cosmo- 
politan as  to  soil,  but  that  methods  of  cultivation  have  given 
it  a  false  appearance  of  preferring  heavy  land. 

Dwarf  spurge  (Euphorbia  exigua)  is  one  of  the  less 
abundant  weeds  which  makes  no  important  contribution  to 
the  economy  of  the  weed  flora,  although  it  is  of  frequent 
occurrence.  The  preference  for  heavy  land  is  very  strong, 
and  it  has  a  marked  objection  to  sand  and  gravel.  It  is 
never  the  chief  weed,  but  on  one  occasion,  at  Inglescombe,  near 


ARABLE  WEEDS.     ASSOCIATION  WITH  SOILS      139 

Bath,  it  was  sub-dominant ;  in  a  large  proportion  of  instances 
it  only  occurs  in  traces,  isolated  individuals  here  and  there 
being  the  sole  representatives. 

The  true  charlock  (Brassica  sinapis]  needs  to  be 
carefully  distinguished  from  some  half  dozen  other  weeds 
which  pass  under  the  same  name.  Charlock  does  not 
exhibit  such  a  marked  preference  for  heavy  soil  as  the  fore- 
going weeds,  but  a  consideration  of  its  dominance  or  scarcity 
on  the  various  soils  show  that  it  has  a  very  strong  preference 
for  the  heavier  land.  On  clay,  heavy  and  medium  loam  and 
chalk  it  is  very  often  dominant,  but  on  the  light  loams  and 
sand  it  comparatively  seldom  reaches  such  a  position.  On  the 
other  hand,  it  is  much  more  often  scarce  on  the  lighter  soil, 
indicating  that  the  habitat  is  less  congenial.  The  preference 
for  heavy  land  in  this  case  is  probably  real,  as  the  plant 
has  no  underground  part  which  aids  in  reproduction,  but  is 
entirely  dependent  upon  seed  for  its  propagation.  Charlock 
is  very  generally  considered  to  be  a  chalk  weed,  but  investiga- 
tion shows  that  in  many  cases  on  the  chalk  the  dominant 
"  charlock  "  is  really  white  mustard  (Brassica  alba]. 

(/3)  Equally  Plentiful  on  Heavy  and  Medium  Soils.-. — The 
weeds  described  above  all  prefer  really  heavy  land  (heavy 
loams  and  clay)  to  any  other  type  of  soil.  A  few  weeds, 
however,  are  as  much  at  home  on  the  medium  loams,  but  are 
much  less  prevalent  on  the  lighter  soils  and  chalk. 

The  large-flowered  field  speedwell  (  Veronica  tournefortii)  is 
really  an  alien,  but  since  its  introduction  it  has  spread  so 
rapidly  that  it  is  now  one  of  the  most  common  of  arable 
weeds  and  has  to  a  large  extent  usurped  the  place  of  the 
ordinary  field  speedwell  (  Veronica  agrestis).  This  fact  has  not 
been  fully  recognised,  and  as  in  many  points  the  two  plants 
very  much  resemble  one  another  V.  tournefortii  is  still 
easily  overlooked  and  confused  with  V.  agrestis  unless  special 
care  be  taken.  In  fact,  although  it  was  reported  from  as 
many  as  29  per  cent,  of  the  fields  visited  in  the  Rothamsted 
investigation  it  was  certainly  present  more  frequently,  as  for 
two  years,  in  Bedfordshire  and  the  West  Country,  we  ourselves 
failed  to  make  the  distinction  and  put  all  records  under  Veronica 
agrestis.  Long,1  too,  fails  to  distinguish  between  the  two  species 
in  his  list  of  weeds,  though  Buckman  '2  in  1855  realised  the 
difference. 


p.  364. 


1  Long,  H.  C.  (1910),  "  Weeds  of  the  Farm  and  Garden,"  p.  399. 

a  Buckman  (1855),  "  On  Agricultural  Weeds,"  Jour.  Roy.  Ag.  Soc.,  XVI, 


140  WEEDS  OF  FARM  LAND 

Heavy  loam  provides  a  rather  more  congenial  habitat  for 
V.  tournefortii  than  clay,  the  plant  is  as  fully  at  home  on 
medium  loam  as  on  the  heavier  soils,  and  it  exhibits  some 
dislike  of  chalky  soil.  This  speedwell  is  occasionally  dominant 
on  various  soils,  usually  on  heavy  loams,  but  probably  as  time 
goes  on  it  will  become  much  more  prevalent  and  widespread 
if  its  progress  continues  to  be  as  rapid  as  it  has  been  of  late 
years. 

Horsetail  (Equisetum  arvense)  and  corn  mint  (Mentha 
arvensis]  are  similar  in  distribution  to  the  large-flowered 
speedwell.  Horsetail  is  often  dominant  on  various  soils, 
chiefly  on  clay  and  medium  loam,  but  it  would  probably 
dominate  to  a  much  greater  extent  if  it  were  allowed  to.  It 
is,  however,  such  a  troublesome  pest  that  special  efforts  are 
directed  towards  its  eradication,  and  the  success  of  these 
efforts  is  shown  by  the  number  of  fields  from  which  the 
weed  is  recorded  as  scarce.  The  long  underground  parts 
enable  the  plant  to  spread  over  wide  areas,  and  it  is  difficult 
to  clear  the  soil  of  the  weed  when  once  it  has  obtained  a  firm 
hold,  especially  on  heavy  land.  It  is  abundant  at  Rothamsted 
on  the  unmanured  plot  of  Broadbalk  wheatfield. 

Orache  (Atriplex  patula]  is  essentially  a  weed  of  heavy 
and  medium  soil,  although  when  it  does  occur  on  the  light 
soil  it  is  often  very  plentiful  and  even  dominant.  Many 
farmers  fail  to  recognise  this  weed,  as  in  some  ways  it  closely 
resembles  fat  hen  (Ckenopodium  album),  especially  in  the  early 
stages  of  growth,  and  the  idea  is  prevalent  that  the  low- 
spreading  plant  of  orache  is  merely  fat  hen  that  has  been  cut 
down  or  has  met  with  other  injury  during  growth  and  so  has 
spread  out  instead  of  growing  into  the  tall  form  characteristic 
of  the  Ckenopodium.  Fat  hen,  however,  is  much  more  widely 
distributed,  and  does  not  show  the  same  preference  for  heavy 
and  medium  soil  as  orache.  Orache  is  not  very  often  domi- 
nant considering  how  often  it  occurs,  but  it  is  usually  present 
in  some  quantity.  The  seeds  are  very  tenacious  of  life  and 
can  survive  burial  in  the  soil  at  considerable  depths1  for 
many  years,  starting  into  active  growth  if  ever  conditions 
become  favourable. 

Nipplewort  (Lapsana  communis]  is  uncommon  and  scarce 
as  an  arable  weed.  It  is  very  rarely  present  in  any  appreci- 
able quantity,  though  it  was  once  seen  dominant  at  Staythorpe 

1  Brenchley,  W.  E.  (1918),  "  Buried  Weed  Seeds,"  Jour.  Ag.  Sci.,  IX, 
pp.  1-31. 


ARABLE  WEEDS.     ASSOCIATION  WITH  SOILS      141 


(Notts), 
weed. 


Possibly  it  is  more  usual  as  a  garden  than  as  a  field 


C.    Weeds  Characteristic  of  Sand  and  very  Light  Soil 
Deficient  in  Lime. 

Much  of  the  sandy  and  very  light  land  in  this  country  in 
its  uncultivated  condition  is  characterised  by  a  marked  defici- 
ency in  lime  content,  so  much  so  that  such  soils  are  often 
said  to  be  "acid"  or  "sour".  Soil  conditions  such  as  these 
are  not  conducive  to  the  healthy  growth  of  a  great  variety  of 
plants,  but  there  are  a  few  weeds  which  are  perfectly  at  home 
and  which  revel  in  the  very  conditions  that  are  untenable  for 
many  others.  The  half  dozen  plants  in  this  category  are 
seldom  seen  on  ordinary  soil,  either  because  there  is  too  much 
lime  present  to  please  them  or  because  they  are  so  impatient 
of  competition  that  directly  other  plants  are  able  to  put  up 
a  fight  the  "  sour  land  "  weeds  give  up  the  struggle  at  once. 

TABLE  VI.— WEEDS  CHARACTERISTIC  OF  SAND  AND  VERY  LIGHT  SOIL, 

DEFICIENT  IN  LIME. 


Percentage  of  Frequency  (=  Number  of 

Times  Seen  per  100  Fields). 

No.  of 

Latin  Name. 

English  Name. 

Times 

Seen. 

All 
Soils. 

Sand 
and 
Bake. 

Sandy 
Loam  and 
Gravel. 

Chalk. 

Other 
Soils. 

Chrysanthemum  segetum 

Corn  marigold  . 

24 

2 

7 

3'5 

_ 

•3 

Gnaphalium  uliginosum 

Marsh  cudweed 

32 

3 

4 

10 

— 

3 

Rumex  acetosella   . 

Sheep's  sorrel   . 

97 

9 

20 

*4 

— 

5 

Scleranthus  anmius 

Annual  knawel 

37 

3 

II 

7 

— 

'3 

Spergula  artensis 
Urtica  urens 

Spurry 
Small  nettle      . 

218 
25 

19 

2 

52 

6 

30 
17 

— 

9 
i'4 

Spurry  {Spergula  arvensis)  (Fig.  36)  is  the  greatest  bug- 
bear in  the  shape  of  weeds  that  farmers  have  to  deal  with  on 
sandy  land.  It  is  an  annual  plant  which  forms  large 
quantities  of  seeds,  and  when  once  fairly  established  it  is 
almost  impossible  to  eradicate  it.  Liming  does  a  great  deal 
to  help,  but  the  amount  of  lime  that  would  be  necessary  to 
eradicate  the  spurry  would  ruin  the  soil,  as  the  dressing 
would  need  to  be  so  abnormally  heavy  that  lime  poisoning 
would  probably  be  set  up.  Spurry  is  so  closely  associated 
with  light  sandy  soils  that  one  expects  to  find  it  there, 
and,  more  than  that,  to  find  it  dominant  in  many  cases.  As 


142 


WEEDS  OF  FARM  LAND 


a  matter  of  fact,  it  is  the  pre-eminent  weed  in  at  least  one- 
third  of  the  cases  in  which  it  is  found,  and  further,  it  is 
relatively  seldom  scarce  except  in  the  few  instances  in  which 


it  appears  on  heavier  land.  The  lighter  the  soil,  the  more 
likely  is  spurry  to  occur,  and  so  it  is  even  more  closely  as- 
sociated with  sand  than  with  sandy  loam  and  gravel. 

Annual  knawel  (Scleranthus  annuus)  (Fig.   37)  is  an  in- 
conspicuous weed  that  is  easily  overlooked,  especially  as  it  is 


ARABLE  WEEDS.     ASSOCIATION  WITH  SOILS      143 

really  not  very  common.  When  it  does  occur,  it  is  often 
present  in  abundance,  especially  on  sand.  It  is  very  rarely 
seen  on  any  soil  heavier  than  gravel. 

Small  nettle  (Urtica  urens)  is  another  weed  that  is  more 


often  seen  on  sand  than  elsewhere,  but  never  on  chalk.  It  is 
not  of  frequent  occurrence,  and  it  is  very  often  scarce,  so  that 
it  plays  little  part  in  the  general  weed  economy. 

Sheep's  sorrel  (Rumex  acetoselta)  (Fig.  38)  is  common  on 
all  the  lighter  soils,  though  it  has  some  preference  for  sand. 
This  may  be  one  of  the  cases  in  which  the  lime  deficiency  has 


144 


WEEDS  OF  FARM  LAND 


more  to  do  with  the  plant's  occurrence  than  has  the  texture  of 
the  soil.     It  occurs  occasionally  on  nearly  all  types  of  land, 


and  is  always  regarded  as  being  an  indicator  of  lack  of  lime, 
but  it  is  not  nearly  as  frequent  on  the  heavier  land  as  is  its 
ally  Rumex  acetosa.  On  sandy  and  gravelly  soils  and  also 
on  peat  sheep's  sorrel  is  frequently  dominant,  and  apart  from 


ARABLE  WEEDS.     ASSOCIATION  WITH  SOILS     145 


arable  land  it  is  a  characteristic  feature  on  sandy  and  gravelly 
heaths  and  commons  where  lime  is  lacking  from  the  soil. 

Corn  marigold  (Chrysanthemum  segetum)  (Fig.  39)  is 
shrouded  in  a 
slight  air  of  mys- 
tery. Obviously 
enough  sandy 
soils  are  con- 
genial to  it,  as  it 
usually  occurs  in 
such  situations 
and  is  relatively 
often  dominant 
there,  whereas 
Buckman  l  states 
that  it  is  an  index 
of  rich  soil.  But 
the  weed  is  by  no 
means  common, 
being  very  local, 
and  even  in  the 
same  district  it  is 
localised  to  cer- 
tain fields.  It  is 
evident  that  some 
other  factor,  in 
addition  to  lime 
deficiency  and 
soil  texture,  de- 
termines its  dis- 
tribution, and  it 
seems  possible 
that  this  factor 
may  be  that  of 
moisture.  A 
comparison  of 
the  number  of 
occurrences  with 
the  number  of  ^IG'  39* — CORN  MARIGOLD  (Chrysanthemum  segetum). 

times  it  is  dominant  suggests  that  the  plant  is  ultra-particular 
as  to  its  habitat  and  is  most  intolerant  of  any  untoward  cir- 
cumstance, but  that  when  its  peculiar  needs  are  met  it  is 

1  Buckman  (1855),  your.  Roy.  Ag.  Soc.,  XVI,  p.  363. 

10 


146 


WEEDS  OF  FARM  LAND 


capable  of  gaining  and  keeping  the  upper  hand  to  the  detri- 
ment of  the  crop  amongst  which  it  finds  itself. 

Marsh  cudweed  (Gnaphalium  uliginosum]  belies  its  name 
utterly  in  its  distribution  as  an  arable  weed.  Far  from  seeking 
moist  spots  in  which  to  flourish  it  is  associated  with  light 
sandy  soils  which  are  well  drained  and  which  seldom  have  any 
superfluous  water  held  up  in  them.  This  is  the  only  one  of 
this  class  of  weeds  which  is  more  frequent  and  abundant  on 
sandy  loam  than  on  sand.  It  is  rarely  present  in  any  quantity, 
but  is  often  scarce,  though  it  was  once  seen  to  be  sub-dominant 
at  Woburn  (Beds).  Buckman  suggests  that  it  is  a  good  in- 
dex of  damp  subsoil. 

D.    Weeds  Associated  with  Chalk. 

The  weeds  that  are  usually  associated  with  chalk  can  be 
divided  into  three  distinct  classes  according  to  the  degree  of 
preference  for  chalky  soil  that  they  exhibit. 

(a)  Plants  characteristic  of  chalk. 

(fr)  Plants  with  a  definite  preference  for  chalk,  but  also  oc- 
curring on  all  soils. 

(c)  Plants  with  a  definite  preference  for  light  and  sandy 
soils  as  well  as  for  chalk. 

(a)  Plants  Characteristic  of  Chalk. — The  true  chalk  lovers 
are  very  few  in  number,  and  even  they  are  not  strictly  confined 
to  the  one  habitat,  though  the  proportion  of  occurrences  on 
other  types  of  soil  is  very  small.  White  mustard  (charlock), 
hardhead,  and  toadflax  are  the  three  outstanding  plants  in 
this  group,  while  corn  gromwell,  wild  mignonette  and  lamb's 
lettuce  are  equally  characteristic  but  much  less  frequently 
seen. 

TABLE  VII.— WEEDS  CHARACTERISTIC  OF  CHALKY  SOILS. 


Percentage  of  Frequency  (=  Number  of  Times 

Seen  per  100  Fields). 

No.  of 

Latin  Name. 

English  Name. 

Times 

Seen. 

All 

Soils. 

Clay  and 
Heavy 
Loam. 

Medium 
Loam. 

Light 
Soils. 

Chalky 
Soil. 

Peat. 

Brassica  alba     . 

White  mustard  . 

72 

6-5 

I 

3 

6 

20 

Centaiirea  nigra 

Hardhead  . 

S6 

5 

I-5 

2 

1-8 

26 

— 

Linaria  vulgaris 

Toadflax     . 

66 

6 

*'5 



2 

33 



Lithospermum  arvense 

Corn  gromwell   . 

21 

2 

•8 

— 

I 

8 

— 

Reseda  lutea 
Valerianella  olitoria 

Wild  mignonette 
Lamb's  lettuce  . 

27 

5 

2'5 

'4 

"5 

I'4 

12 

3 

— 

ARABLE  WEEDS.     ASSOCIATION  WITH  SOILS     147 

White  mustard  or  charlock  (Brassica  alba]  is  often  found 
growing  alongside  the  ordinary  charlock  (Brassica  sinapis]  on 
chalky  soils,  though  it  is  not  so  frequent  in  occurrence  even 
in  such  favoured  situations,  but  whereas  the  Brassica  sinapis 
is  abundant  on  all  types  of  soil  with  a  leaning  towards  the 
heavy  land,  Brassica  alba  is  rarely  seen  except  on  typical 
chalk  land  and  in  a  less  degree  on  light  soils.  The  two 
species  are  very  similar  in  habitat  and  colour  of  flower,  and 
farmers  rarely  distinguish  between  the  two  forms,  the  chief 
difference  being  in  the  shape  of  the  leaves  and  the  character 
of  the  fruits.  When  white  mustard  does  occur  it  is  very  often 
dominant,  particularly  on  chalk,  where  it  is  the  chief  weed 
every  second  time  that  it  occurs.  Curiously  enough,  though 
the  species  is  so  uncommon  on  the  heavy  and  medium  land, 
yet  in  such  situations  it  is  sometimes  dominant  instead  of 
being  occasional. or  scarce,  as  is  usually  the  case  with  plants 
that  show  preference  for  special  types  of  soil  when  they  occur 
outside  the  preferred  habitat. 

Hardhead  (Centaur ea  nigrd]  is  as  common  on  chalky  soil 
as  the  white  mustard,  but  it  is  more  or  less  insignificant  in 
quantity,  and  never  reaches  a  position  of  dominance.  The 
plants  are  larger  and  therefore  attract  attention,  but  the 
species  is  more  associated  with  pasture  than  with  arable  land. 

Toadflax  (Linaria  vulgaris)  and  wild  mignonette  (Reseda 
luted)  are  always  connected  in  the  popular  mind  with  chalky 
land,  and  indeed  they  seem  curiously  characteristic  and  con- 
spicuous, although  they  are  rarely  present  in  any  considerable 
quantity.  Corn  gromwell  (Lithospermum  arvense)  and  lamb's 
lettuce  (  Valerianetla  olitorid}  are  most  insignificant,  occurring 
but  seldom  and  in  very  small  quantities,  but  nevertheless  they 
are  just  as  characteristic  of  chalky  soils  as  are  the  more  abun- 
dant species  like  white  mustard  and  toadflax. 

(b]  Plants  with  a  Definite  Preference  for  Chalk,  but  also 
occurring  on  all  Soils. — This  class  of  weeds  is  much  better  re- 
presented than  that  of  plants  characteristic  of  chalk.  The 
plants  in  this  section  do  not  exhibit  violent  dislike  to  any  type 
of  soil,  but  they  are  certainly  much  more  often  associated  with 
chalky  land  than  with  any  other.  Some  of  the  commoner 
weeds  come  under  this  heading,  such  as  pimpernel,  fumitory, 
field  pansy,  and  campion,  and  only  a  very  few  are  at  all 
infrequent  'in  distribution  on  arable  land,  these  being  hog- 
weed,  greater  knapweed,  round  leaved  toadflax,  and  wild  carrot. 
This  is  only  another  instance  of  what  usually  occurs.  Plant 


i48 


WEEDS  OF  FARM  LAND 


species  that  are  really  characteristic  of  any  type  of  soil  are 
few  in  number  and  comparatively  infrequent  in  distribution, 
whereas  plants  which  merely  exhibit  a  preference  for  a  partic- 
ular soil  are  represented  by  several  species,  and  are  far  more 
often  met  with. 


TABLE  VIII.— WEEDS  WITH  A  DEFINITE  PREFERENCE  FOR  CHALK  BUT 
ALSO  OCCURRING  ON  ALL  SOILS. 


8 

Percentage  of  Frequency  (=  Number  of 
Times  Seen  per  100  Fields). 

Latin  Name. 

English  Name. 

§i 

^ 

G  . 

o 

1 

ll 

19 

|| 

JjVj 

I'S 

1 

9 

Kco 

3H 

JlO 

5* 

PH 

Anagallis  arvensis 

Pimpernel 

205 

18 

18 

18 

16 

40 

_ 

Bartsia  odontites  . 

Red  bartsia 

74 

7 

7 

7 

4 

15 



Centaurea  scabiosa 

Greater  knapweed 

34 

3 

'4 

2'6 

3 

9 



Daucus  carota 

Wild  carrot 

38 

3*4 

•8 

4  • 

2 

12 



Fumaria  officinalis 

Fumitory 

230 

21 

12 

25 

21 

31 



Heracleum  sphondyliun 
Linaria  spuria 

Hogweed   . 
Round-leaved  toadflax 

33 

8 

3 
7 

3 

"4 

4 
1-6 

I 
•2 

9 

2 

~ 

Lychnis  vespcrtina 

White  campion  . 

191 

17 

8 

16 

18 

31 



Ranunculus  acris  . 

Tall  buttercup    . 

43 

4 

5 

1-6 

3 

7 

Scabiosa  arvensis 

Field  scabious    . 

121 

ii 

4 

8 

8 

37 

Silene  injlata 

Bladder  campion 

IOO 

9 

3 

8 

6 

30 

— 

Taraxacum  vulgare 

Dandelion 

96 

9 

ro 

8 

5 

18 

23 

Viola  tricolor 

Pansy 

245 

22 

9 

19 

25 

33 

69 

Of  all  the  weeds  classified  in  this  list  field  scabious  {Scabiosa 
arvensis),  bladder  campion  (Silene  inflata},  wild  carrot  (Daucus 
carota),  and  greater  knapweed  (Centaurea  scabiosa}  show  the 
greater  preference  for  chalky  soil,  though  pimpernel  (Anagallis 
arvensis]  and  hogweed  (Heracleum  sphondylium)  run  them 
very  close. 

Field  scabious  (Scabiosa  arvensis)  is  quite  commonly  dis- 
tributed, but  it  rarely  occurs  in  any  quantity,  and  was  never 
seen  to  reach  a  position  of  dominance. 

Bladder  campion  {Silene  inflata)  is  perhaps  rather  less 
frequently  seen  than  the  scabious,  but  it  occurs  in  greater 
abundance,  and  occasionally  forms  the  chief  weed  in  the  flora 
on  various  types  of  land. 

Wild  carrot  (Daucus  carota)  is  probably  less  usual  as  an 
arable  than  as  a  pasture  weed,  but  in  spite  of  its  infrequent 
occurrence  it  is  sometimes  present  in  such  abundance  as  to  be 
dominant  on  light  and  chalky  soils. 

Greater  knapweed  (Centaurea  scabiosa)  is  another  of  the 


ARABLE  WEEDS.     ASSOCIATION  WITH  SOILS      149 

more  uncommon  weeds,  being  much  less  frequent  than  its 
ally  C.  nigra.  Usually  it  is  not  present  in  any  abundance,  but 
it  was  once  seen  dominant  on  sand  in  Norfolk. 

Poor-man's-weather-glass  or  pimpernel  (Anagallis  arvensis) 
is  one  of  the  more  insignificant  weeds  which  are  fairly  wide- 
spread but  rarely  occur  in  any  quantity.  Nevertheless,  it  is 
in  no  danger  of  being  overlooked  as  it  attracts  much  interest 
and  attention  from  the  fact  that  it  is  said  to  close  on  the 
approach  of  rain,  thus  providing  a  useful  weather  glass  for 
country  folk.  Very  occasionally  it  is  present  in  such  abund- 
ance as  to  be  dominant,  and  it  has  been  found  so  both  on 
heavy  clay.and  chalky  loam. 

Hog  weed  (H eracleum^  sphondylium)  is  not  very  common  as 
an  arable  weed,  as  it  much  prefers  the  hedgerow  for  its  habitat. 
It  never  dominates  in  the  fields  and  is  frequently  represented 
by  solitary  individuals,  interlopers  that  have  wandered  out 
from  their  normal  position  in  the  hedges. 

A  few  of  the  more  common  weeds,  such  as  fumitory, 
campion,  field  pansy,  are  not  quite  as  closely  associated  with 
chalky  soil  as  those  described  above,  though  the  preference  is 
still  very  marked. 

Fumitory  (Fumaria  officinalis]  is  ephemeral  in  nature, 
and  disappears  from  the  fields  at  a  comparatively  early  date, 
so  that  it  may  be  more  abundant  in  reality  than  the  figures 
indicate.  It  is  quite  frequently  dominant,  and  still  more  often 
scarce,  but  both  these  observations  may  need  to  be  modified 
in  consideration  of  the  fugitive  nature  of  the  species.  As  a 
matter  of  fact  Fumaria  offidnalis  includes  a  number  of  species 
which  have  not  been  distinguished  in  the  field,  and  some 
of  these  are  more  ephemeral  than  others,  so  that  the  records 
obtained  for  fumitory  in  the  later  months  of  the  season 
are  largely  dependent  upon  the  particular  species  occurring  in 
the  districts  examined. 

White  campion  (Lychnis  vespertind)  is  very  widely  scattered, 
but  it  is  seldom  present  in  any  amount,  and  indeed  is  scarce 
in  two  out  of  every  five  times  it  occurs.  It  is  quite  probable 
that  most  of  the  seed  is  introduced  with  clover  and  other  small 
crop  seeds,  and  this  would  largely  account  for  the  widespread 
distribution  and  for  the  fewness  of  the  plants  found. 

Field  pansy  ( Viola  tricolor]  is  also  commonly  found  in 
small  quantities,  and  was  only  once  seen  dominant  on  gravel 
in  Nottinghamshire. 

Red  bartsia,  tall  buttercup,  dandelion,  and  round-leaved 


WEEDS  OF  FARM  LAND 


toadflax  are  less  usually  seen  in  arable  fields,  and  are  not  often 
present  in  any  quantity.  Very  occasionally  red  bartsia  and 
tall  buttercup  dominate,  but  generally  they  are  quite  insignifi- 
cant. Red  bartsia  (Bartsia  odontites],  however,  attracts  a 
certain  amount  of  unfavourable  notice  on  account  of  its  semi- 
parasitic  nature,  described  elsewhere  (p.  102). 

(c)  Plants  with  a  Definite  Preference  for  Light  and  Sandy 
Soils  as  well  as  for  Chalk. 

TABLE  IX.— WEEDS  WITH    A  DEFINITE    PREFERENCE    FOR    LIGHT   AND 
SANDY  SOILS  AS  WELL  AS  FOR  CHALK. 


| 

Percentage  of  Frequency  (=  Number 
of  T.mes  Seen  per  100  Fields). 

Latin  Name. 

English  Name. 

y* 

rs 

^ 

a 

. 

. 

6 

2 

1 

< 

$ 

_D 

-5 

i 

.£P 

ja 

0 

rt 
O 

OH 

Car  duns  nutans  . 

Musk  thistle     . 

21 

2 

_ 

1-6 

2-4 

4 



Filago  germanica 

Cudweed 

15 

rs 

— 

i 

2*2 

1*3 



Geranium  pusilkim 

Small-flowered  crane's-bill 
Henbit 

30 

OQ 

2-7 

•8 

2 

3-2 

5 



Legousia  hybrida 

Corn  campanula 

37 

3 

i-i 

2'6 

4 

6 



Lycopsis  arvensis 

Small  bugloss 

30 

2-7 

— 

— 

5'5 

i'3 



Veronica  serpyllifolla 

Thyme-leaved    speedwell 

7 

•6 

~ 

~ 

~ 

~ 

The  species  in  this  list  are  on  the  whole  very  insignificant 
members  of  the  weed  flora.  Not  one  of  them  occurs  at  all 
frequently,  and  it  is  very  seldom  that  any  are  present  in  any 
abundance.  On  one  or  two  occasions  musk  thistle  (Carduus 
nutans]  and  small-flowered  crane's-bill  (Geranium  pusillum)  were 
the  chief  weeds  in  the  fields,  but  none  of  the  others  were  ever 
dominant.  Yet,  in  spite  of  their  comparative  scarcity,  several 
of  these  plants  are  very  interesting,  and  attract  much  attention. 
Musk  thistle,  cudweed,  henbit,  corn  campanula,  and  small 
bugloss  all  have  peculiar  characteristics  of  habit  or  colour  which 
mark  them  out  among  their  associates,  and  consequently  an 
observer  often  receives  the  impression  that  these  weeds  are 
more  common  than  they  really  are,  and  the  results  of  the 
numerical  analysis  come  in  the  nature  of  a  surprise. 

E.    Weeds  Associated  with  Peat  Soils. 

Many  peat  soils  are  particularly  difficult  to  cultivate  owing 
to  their  peculiar  nature,  and  in  most  cases  such  soils  are  left 
to  their  own  devices  or  used  for  grazing  or  hay  instead  of  for 


ARABLE  WEEDS.     ASSOCIATION  WITH  SOILS     151 


arable  cultivation.  This,  of  course,  does  not  apply  to  the 
Fen  land,  which  is  of  a  specially  rich  nature,  and  which  is  not 
acid  like  many  of  the  other  peat  lands. 

Weed  Flora  of  Twelve  Fields  on  Everton  Carr,  Arranged  in 
Numerical  Order  of  Frequency. 


Latin  Name. 

English  Name. 

No.  of 
Times 
Seen. 

No.  of 
Times 
Dominant. 

Remarks. 

Polygonum  persecaria  . 

Willow-weed 

IO 

4 

Spergula  arvensis 

Spurry 

9 

4 

Rumex  acetosclla 

Sheep's  sorrel 

9 

2 

Also  once  sub- 

dominant. 

Galeopsis  tetrahit 

Hemp  nettle  . 

9 

I 

Viola  tricolor 

Field  pansy  . 

8 

-  — 

Often  in  patches. 

Agrostis  stolonifera  ?   . 

Bent  grass     . 

5 

2 

Sometimes  in 

patches. 

Chenopodium  album     . 

Fat  hen 

5 



Polygonum  convolvulus 

Black  bindweed 

5 

— 

Taraxacum  vulgare 

Dandelion 

3 

— 

Stellaria  media   . 

Chickweed     . 

2 

— 

Only  in  small 

amount. 

Equisetum  arvense 

Horsetail 

2 

— 

Atriplex  patula   . 

Orache  . 

2 

— 

Potentilla  anserina 

Silverweed     . 

2 



Polygonum  aviculare  . 

Knotgrass 

2 

— 

Hypochceris  radicata   . 

Cat's  ear 

2 

— 

Rumex  crispus 

Curled  dock   . 

2 

— 

Poa  annua  . 

Annual  meadow 

2 

— 

Scarce  on  both 

grass 

occasions. 

Brassica  sinapis  . 

Charlock 

— 

Sonchtis  arvensis 

Corn  sow-thistle     . 



Anthemis  arvensis 

Corn  chamomile    . 



Achillea  millifolium    . 

Yarrow  . 

,  — 

Ranunculus  repens 

Creeping  buttercup 

— 

Senecio  vulgaris  . 

Groundsel 



All  scarce. 

Lychnis  ftos-cuculi 

Ragged  robin 

— 

Matricaria  inodora 

Scentless  mayweed 

I 

— 

The  peat  on  Everton  Carr,  Nottinghamshire,  provides  an 
interesting  instance  of  the  weeds  that  occur  when  wet,  acid 
peat  land  is  cultivated.  The  weed  flora  is  very  restricted  in 
the  number  of  species  composing  it,  but  a  few  are  markedly 
characteristic  of  the  situation  and  occur  in  most  fields,  often 
in  considerable  quantity  :  Willow-weed  (Polygonum persecaria}, 
spurry  (Spergula  arvensis),  sheep's  sorrel  (Rumex  acetosella), 
and  bent  grass  (Agrostis  stolonifera .?),  are  usually  present  and 
often  dominant,  and  hemp  nettle  (Galeopsis  tetrahif)  is  also 
very  common,  though  it  seldom  dominates  the  whole  of  a 


152  WEEDS  OF  FARM  LAND 

field.  In  addition  to  these  fat  hen  (Chenopodium  album},  black 
bindweed  (Polygonum  convolvulus),  and  field  pansy  ( Viola 
tricolor]  occur  frequently  in  greater  or  less  abundance.  The 
other  species  found  are  less  characteristic  of  peat  soils  and 
are  more  erratic  in  their  distribution.  An  analysis  of  the 
weeds  seen  on  twelve  fields  on  Eyerton  Carr  on  28th  June, 
1915,  may  be  of  interest,  as  the  list  (see  page  151)  shows 
very  clearly  how  severely  the  personnel  of  the  weed  flora  is 
limited  by  the  habitat. 

COMPARISON  OF  DISTRIBUTION  OF  ARABLE  WEEDS  AS 
RECORDED  BY  VARIOUS  OBSERVERS. 

It  is  instructive  to  compare  the  absolute  quantitative  results 
obtained  by  the  Rothamsted  methods  of  working  with  the 
more  empirical  results  set  forth  by  other  workers  from  records 
of  practical  experience  and  accumulated  general  observations. 
Two  convenient  lists  are  available,  given  by  Buckman  1  (1855) 
and  Long2  (1910). 

A  close  comparison  of  the  habitats  of  the  various  weeds  as 
given  by  the  three  sets  of  observations  shows  most  remarkable 
agreement.  This  agreement  is  absolute,  except  with  regard  to 
some  thirty-seven  species,  and  with  these  the  discrepancy 
is  usually  slight  and  due  to  the  fact  that  one  or  other  investi- 
gator has  made  a  closer  association  of  the  weed  in  question 
with  some  particular  soil.  This  may  easily  happen,  as  local 
variations  in  distribution  are  bound  to  influence  the  judgment 
of  the  worker  to  some  extent.  For  instance,  Long  and  Buck- 
man associate  Euphorbia  exigua  with  loams,  whereas  the 
writer  finds  it  on  all  types  of  soil,  with  some  preference  for 
heavier  land.  Again,  Long  associates  Scabiosa  arvensis  with 
all  soils  indifferently.  Buckman  confines  it  to  calcareous  land, 
whereas  the  writer  finds  it  on  all  soils,  with  a  preference  for 
chalk,  thus  reconciling  the  opinions  of  the  other  two  authorities. 
Similar  reconciliations  can  be  effected  in  most  instances  where 
discrepancy  exists,  and  the  only  cases  in  which  the  variations 
in  the  lists  are  significant  are  given  in  the  following  table,  any 
result  which  is  seriously  disputed  being  put  into  italics : — 

1  Buckman  (1855),  "On  Agricultural  Weeds,"  Jour.  Roy.  Agric.  Soc.,  XVI, 

PP-  359-367- 

2  Long,  H.  C.  (1910),  "  Common  Weeds  of  the  Farm  and  Garden,"  pp. 
384-408. 


ARABLE  WEEDS.     ASSOCIATION  WITH  SOILS     153 


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154  WEEDS  OF  FARM  LAND 

Some  of  the  discrepancies  in  the  above  table  are  such  as 
might  be  reconciled  or  eliminated  with  a  wider  range  of  ob- 
servations, but  a  few  of  the  statements  are  so  diametrically 
opposed  to  one  another  that  it  is  difficult  to  see  how  they 
could  be  made  to  agree. 

Alopecurus  agrestis  is  peculiarly  at  home  on  heavy  clay 
and  the  heavier  soils,  so  much  so  that  it  seems  to  be  character- 
istic. In  the  Rothamsted  experiments  it  was  only  seen  once 
on  sand  and  four  times  on  gravel,  out  of  a  total  of  fifty-four 
observations,  a  fact  which  gives  no  corroboration  to  Long's 
statement  that  it  is  a  weed  of  dry  sandy  soils. 

Papaver  rhceas  is  popularly  associated  with  light  soils,  and 
indeed,  often  occurs  so  abundantly  in  such  situations  as  to 
nickname  the  whole  district,  e.g.  "Poppyland"  in  Norfolk. 
Nevertheless,  an  unbiassed  analysis  shows  that  whereas  poppies 
are  often  overwhelmingly  abundant  on  some  light  soils,  yet 
they  are  universally  distributed  over  nearly  all  soils,  although 
they  are  present  in  smaller  quantities  on  the  really  heavy 
types  of  land.  It  has  already  been  pointed  out  that  Papaver 
rhceas  was  observed  as  a  dominant  on  every  kind  of  soil  except 
clay  and  peat,  so  that  there  seems  to  be  no  justification  for 
Buckman's  remark  that  this  species  is  "  a  most  exact  indicator 
of  sandy  soil  ".  As  a  matter  of  fact,  poppies  are  impatient  of 
certain  types  of  sandy  soil,  and  the  acid  sands  that  bear  heavy 
.crops  of  spurry  rarely  carry  many  poppies,  while  the  chalky 
sands  that  are  so  congenial  to  the  latter  are  unfavourable  to 
the  growth  of  spurry. 

Long's  statement  that  Rumex  acetosella  occurs  on  all  dry 
soils  is  misleading,  as  this  includes  the  chalky  land  which  is 
obnoxious  to  the  species.  The  writer's  observations  go  to 
show  that  sheep's  sorrel  is  characteristic  of  light  and  sandy 
land,  but  that  it  is  seldom  seen  on  chalk,  so  much  so  that  the 
plant  is  regarded  as  one  of  the  few  "  indicators  "  of  acid  soil. 
Being  shallow  rooted  it  may  be  found  as  a  denizen  of  a  very 
thin  layer  of  sour  land  overlying  chalk,  as  happens  in  the 
"  bake  "  on  the  top  of  some  of  the  Wiltshire  Chalk  downs. 

Spergula  arvensis  is  another  plant  that  indicates  a  deficiency 
of  chalk,  and  again  it  is  misleading  to  describe  it  as  occurring 
on  all  soils.  The  plant  is  still  more  characteristic  of  sand  and 
very  light  soil  than  the  sheep's  sorrel,  and  even  when  it  puts 
in  an  occasional  appearance  on  heavier  land  it  is  usually  very 
scarce.  Its  dislike  of  chalk  is  so  marked  that  although  it  has 
been  noted  218  times  it  has  never  once  been  observed  on 


ARABLE  WEEDS.     ASSOCIATION  WITH  SOILS     155 

any    type  of  calcareous  land,  whether    chalk,   chalky    loam, 
chalky  sand,  or  red  land. 

In  a  few  cases  the  differences  between  the  three  tables  are 
possibly  caused  by  the  local  distribution  of  certain  weeds.  If 
plants  are  at  all  localised  it  is  quite  likely  that  utterly  different 
results  may  be  obtained  by  various  workers  or  by  the  same 
worker  in  different  areas.  As  an  instance  of  this,  Scandix pecten 
{shepherd's  needle)  may  be  cited.  In  Wiltshire,  in  1911,  this 
plant  was  almost  exclusively  associated  with  chalk  and  red 
land,  and  it  occurred  frequently  enough  to  be  considered  a 
chalk  lover.  In  Norfolk,  in  1912,  and  in  Notts  and  Derby 
in  1915  the  same  species  was  not  once  seen  on  chalk,  and 
only  very  rarely  on  chalky  loam,  so  that  it  behaved  practically 
as  a  calcifuge.  In  Bedfordshire,  in  1910,  it  was  not  often 
seen,  but  it  was  associated  with  several  kinds  of  soil  without 
showing  much  preference.  This  at  once  shows  how  the 
difference  may  have  arisen  between  Long's  and  the  writer's 
observations  on  this  species,  and  also  affords  an  indication 
that  if  more  data  were  forthcoming  many  of  the  other  differ- 
ences would  be  modified  or  eliminated. 


156 


WEEDS  OK  FARM  LAND 


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ARABLE  WEEDS.     ASSOCIATION  WITH  SOILS     157 


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CHAPTER  X. 

ARABLE  WEEDS.     ASSOCIATION  WITH  CROPS. 

IT  has  already  been  pointed  out  that  one  of  the  chief  factors 
in  determining  the  abundance  or  scarcity  of  a  particular  weed 
is  the  degree  of  competition  it  is  able  to  withstand  success- 
fully, and  furthermore,  that  the  above-ground  struggle  for 
light  is  as  important  as  the  underground  struggle  for  food 
and  water.  This  being  the  case,  the  habit  of  growth  of  the 
various  crops  and  the  differing  systems  under  which  they  are 
cultivated  have  a  great  deal  to  do  with  determining  the  com- 
position of  the  weed  flora.  A  normal  crop  of  clover  or 
temporary  grass  grows  strongly  and  completely  covers  the 
ground,  so  that  it  is  impossible  for  the  majority  of  weeds  to 
live  at  all  except  in  bare  patches  where  the  crop  has  failed. 
Consequently  very  few  of  the  ordinary  local  farm  weeds  are 
to  be  found  among  such  a  crop,  unless  the  latter  has  come  so 
badly  that  the  ground  is  not  covered  and  the  weeds  have 
an  opportunity  to  live.  On  the  other  hand,  there  are  a  few 
weeds,  like  geranium,  campion,  and  field  madder,  which  are 
specially  fitted  to  grow  among  a  smothering  crop,  and  these 
plants  are  generally  to  be  found  in  the  clover.  The  seeds  are 
carried  with  the  crop  seeds  and  the  weeds  flourish  among  the 
crops,  but  they  are  so  impatient  of  cultivation,  or  are  so 
unable  to  withstand  the  open  situation  among  cereals  and 
roots,  that  very  few  of  them  survive  when  once  the  clover  or 
grass  has  been  removed  from  the  ground. 

Amongst  cereal  crops  matters  are  quite  otherwise.  The 
crop  plants  grow  in  regular  rows,  well  spaced  out,  and  for  a 
long  period  during  early  growth  the  plants  are  small  and  offer 
comparatively  little  competition  to  the  weeds  except  in  the 
rows  in  which  they  are  sown.  This  is  most  favourable  for 
the  weeds,  and  if  it  were  not  for  occasional  cultivation  the 
crop  would  have  a  very  poor  chance  as  it  would  become 
choked  out  or  smothered  by  the  weeds.  Indeed,  this  is 
occasionally  seen  to  happen,  especially  on  light  sandy  land  on 

159 


160  WEEDS  OF  FARM  LAND 

which,  owing  to  a  deficiency  of  lime  in  the  soil,  spurry  is  ramp- 
ant. Such  soils  are  sometimes  loaded  with  buried  spurry 
seed,  and  if  the  season  be  favourable  to  the  germination  and 
early  growth  of  the  plant  it  comes  up  strongly  in  such 
enormous  quantities  that  no  amount  of  cultivation,  short  of 
hand  pulling  at  great  expense,  is  able  to  remove  sufficient 
of  it  to  prevent  it  from  becoming  a  most  serious  competitor 
of  the  crop.  Even  when  it  is  possible  to  make  a  fair  clearance 
some  parts  of  the  fields  always  seem  to  defy  all  efforts  and 
grow  crops  of  spurry  instead  of  corn,  thus  reducing  the  profit- 
able crop  and  causing  a  considerable  monetary  loss.  On  less 
acid  soils  of  light  types  the  poppy  behaves  in  much  the  same 
way,  but  as  this  weed  grows  upright  instead  of  sprawling  over 
the  ground  it  gives  the  crop  a  slightly  better  chance.  The 
time  at  which  the  crop  is  sown  and  the  nature  of  the  growing 
season  have  a  great  effect  upon  the  variety  and  abundance  of 
weeds.  Autumn  sown  wheat  germinates,  makes  a  little 
growth,  and  then  waits  until  the  following  spring  before  it 
makes  much  headway.  Many  of  the  weed  seeds  germinate 
very  freely  in  the  autumn,  seedlings  grow  up  among  the 
wheat  and  are  well  established  by  the  spring.  Cultivating 
between  the  drills  removes  many  of  them  at  that  time,  but  a 
very  considerable  proportion  remain  to  come  into  competition 
with  the  wheat.  Charlock,  for  instance,  holds  its  own  in  the 
drill,  and  it  is  quite  usual  to  see  fields  of  wheat  flaming  yellow 
with  charlock  in  the  spring  sunshine.  If  the  wheat  gets  a 
good  start  it  will  grow  so  rapidly  that  it  overtops  the  weeds, 
and  by  depriving  them  of  light  keep  them  under  to  a  great 
extent.  If  the  season  be  unfavourable,  however,  wheat  and 
weeds  have  to  continue  in  competition,  with  the  result  that  the 
wheat  plants  suffer  from  overcrowding  and  the  crop  is  short. 

It  is  much  more  easy  to  cope  with  the  weeds  when  corn 
is  sown  in  the  spring.  The  land  is  laid  up  roughly  in  the 
autumn  and  multitudes  of  weed  seeds  germinate  and  begin  to 
flourish,  only  to  be  turned  under  and  destroyed  when  the  land 
is  ploughed  in  the  spring  previous  to  sowing.  If  two  or  three 
ploughings  are  given  before  sowing,  more  and  more  of  the 
weed  seeds  are  thus  put  out  of  the  way  of  doing  harm.  When 
the  crop  is  sown  it  grows  straight  away  after  the  seedlings  are 
up,  and  unless  the  weather  is  exceptionally  droughty  there  is 
no  check  t®  development.  The  weed  seeds  begin  to  germinate 
as  well  but  they  have  little  chance  among  the  crop,  as  before 
they  get  a  good  foothold  the  crop  plants  are  so  lusty  that  the 
weeds  are  injured  by  competition  in  a  very  early  stage  of 


ARABLE  WEEDS.     ASSOCIATION  WITH  CROPS      161 

growth,  and  never  have  a  chance  to  grow  big  enough  to  do  any 
damage.  Thus  it  happens  that  good  strong  crops  of  spring- 
sown  wheat,  oats,  and  barley  are  remarkably  free  from  weeds 
during  the  growing  season.  In  July  and  August  the  ground 
below  the  plant  is  clean,  with  only  an  occasional  sickly  weed 
struggling  for  existence  here  and  there.  It  is  sometimes  said 
that  the  best  way  to  get  rid  of  weeds  is  to  keep  the  crops 
growing  well  and  strongly,  enabling  them  to  carry  out  the 
work  of  eradication  themselves  without  much  artificial  aid. 
If  the  season  be  unfavourable  and  a  long  drought  prevents  the 
corn  from  growing  away  strongly  the  weeds  have  a  much 
better  chance.  Some  of  them  can  stand  drought  well,  and  as 
at  such  times  they  often  grow  more  rapidly  than  the  crop  they 
are  able  to  come  into  strong  competition. 

Root  crops  are  kept  so  well  cultivated  that  there  is  no 
definite  evidence  to  show  how  they  would  behave  towards 
weeds  if  they  were  left  to  themselves.  The  ground  is  very 
well  prepared  beforehand  and  the  seeds  are  sown  comparatively 
.  late  in  the  season,  with  the  result  that  large  numbers  of  the 
weed  seeds  have  started  into  growth  and  been  destroyed  before 
the  crop  is  sown.  The  constant  use  of  the  hoe  during  growth 
does  not  give  the  weeds  any  chance,  and  it  is  for  this  reason 
that  roots  are  considered  to  be  such  valuable  "  cleaning  crops  ". 
This  general  association  of  weeds  with  crops  is  obvious, 
but  detailed  investigation  shows  that  a  much  closer  connection 
exists  between  certain  crops  and  particular  species  of  weeds. 
Whilst  most  weeds  of  any  importance  are  to  be  found  associated 
to  some  extent  with  every  crop,  yet  many  of  them  are  specially 
encouraged  or  discouraged  by  one  crop  or  another. 

Comparatively  few  weeds  are  equally  prevalent  among  all 
crops  and  these  few  comprise  some  of  the  most  abundant  and 
widely  distributed  plants.  The  others  all  have  some  special 
relation  to  the  crops,  either  of  aversion  or  sympathy.  In  con- 
sidering this  question  it  is  generally  of  little  use  to  take  into 
account  those  weeds  which  occur  very  seldom,  as  the  data  are 
not  often  sufficiently  reliable  to  base  conclusions  upon.  In  a 
few  cases,  however,  this  rule  has  been  departed  from,  where 
the  indications  of  association  are  particularly  marked. 

An  examination  of  the  lists  of  the  percentage  of  frequency 
of  the  chief  weeds  among  the  different  classes  of  crops  shows 
that  roots,  seeds,  peas,  and  beans  have  the  most  direct  influence 
upon  the  weed  flora.  The  weeds  that  are  encouraged  or 
discouraged  by  these  crops  divide  up  into  distinct  classes  with 

ii 


l62 


WEEDS  OF  FARM  LAND 


hardly  any  overlapping,  so  that  a  plant  which  appears  under 
one  heading  is  very  seldom  found  under  another.  The  cereals, 
however,  do  not  act  quite  in  the  same  way.  As  a  whole  they 
form  an  indifferent  body  of  crops,  because  hardly  any  weeds 
are  either  specially  associated  with  them  or  usually  absent 
from  among  them.  Some  differences  are  evident  between 
the  cereals,  weeds  that  are  common  among  wheat  being 
often  scarce  among  barley,  etc.,  but  the  division  is  not  so  clear 
as  with  the  other  classes  of  crops.  For  this  reason  a  considera- 
tion of  the  association  of  weeds  with  cereals  is  postponed  for 
a  time,  because  all  the  chief  weeds  can  be  classified  under 
other  headings. 

For  this  purpose  arable  weeds  may  be  summarised  thus  : — 

(1)  Weeds  that  are  found  as  often  among   one  crop  as 
another. 

(2)  (a)  Weeds  specially  associated  with  root  crops. 
(ft)  Weeds  discouraged  by  root  crops. 

(3)  W  (a)  Weeds  specially  associated  with  temporary  grass 
or  clover  ("  seeds  "). 

Q9)  Weeds    specially    associated    with    temporary 
grass  or  clover  and  wheat  crops. 

(ft)  Weeds  discouraged  by  temporary  grass  or  clover 
("seeds"). 

(4)  (a)  Weeds  specially  associated  with  peas  and  beans. 
(ft)  Weeds  discouraged  by  peas  and  beans. 

I.    Weeds  that  are  Found  as  often  Among  one  Crop  as  Another. 

TABLE  X.— WEEDS  THAT  ARE  FOUND  AS  OFTEN    AMONG  ONE  CROP  AS 

ANOTHER. 


Percentage  of  Frequency  (  =  Number  of  Times 

Seen  per  100  Fields). 

Latin  Name. 

English  Name. 

Peas 

All 
Crops. 

Wheat. 

Barley. 

Oats. 

Roots. 

Seeds. 

and 
Beans. 

Brassica  sinapis  . 

Charlock    . 

34 

37 

42 

50 

26 

25 

34 

Capsella  bursa-pastoris 

Shepherd's  purse 

30 

38 

30 

33 

27 

28 

31 

Cirsium  arvense  . 

Creeping  thistle 

73 

65 

74 

67 

75 

63 

69 

Convolvulus  arvensis 

Bindweed  . 

54 

56 

67 

52 

51 

43 

45 

Linaria  vulgar  is  . 

Toadflax     . 

6 

5 

7 

5 

4 

8 

3 

Rumex  acetosella 

Sheep's  sorrel 

9 

6 

4 

15 

7 

10 

7 

Rumex  crispus 

Curled  dock 

4i 

50 

39 

44 

30 

41 

48 

Senecio  vulgaris  . 

Groundsel  . 

33 

33 

26 

37 

32 

33 

43 

Sonchus  arvensis  . 

Corn  sow-thistle. 

27 

26 

34 

24 

17 

37 

34 

Veronica  agrestis 

Field  speedwell  . 

19 

23 

28 

24 

13 

13 

22 

ARABLE  WEEDS.     ASSOCIATION  WITH  CROPS      163 

The  plants  in  Table  X  are  commonly  associated  with 
every  type  of  crop,  and  some  of  them  are  among  the  most 
frequent  and  abundant  weeds.  A  few  of  them,  however,  are 
more  specially  favoured  by  certain  crops,  this  being  shown  by 
their  relative  abundance  and  the  number  of  times  that  they 
usurp  the  position  of  dominant  weeds.  Charlock  (Brassica 
sinapis]  is  often  dominant  among  all  crops,  but  particularly 
in  wheat  and  oats.  Field  bindweed  (Convolvulus  arvensis) 
dominates  very  frequently,  specially  among  barley  and  on 
fallow  land.  Creeping  thistle  (Cirsium  arvense),  on  the  other 
hand,  is  abundantly  dominant  among  all  crops,  if  allowed,  but 
it  is  rather  less  favoured  by  wheat,  oats  and  seeds.  The  rest  of 
the  weeds  in  this  class  are  not  often  present  in  great  quantity, 
partly  because  they  are  so  steadily  eradicated  when  seen  that 
they  do  not  have  a  fair  chance.  Sheep's  sorrel  (Rumex  aceto- 
sella]  and  groundsel  (Senecio  vulgaris)  flourish  best  among 
seeds ;  corn  sow-thistle  (Sonchus  arvensis]  is  seldom  very 
plentiful  except  with  barley  ;  field  speedwell  (  Veronica  agrestis] 
is  sometimes  abundant  among  oats  and  peas  and  beans.  Some 
of  the  weeds,  again,  are  frequently  present  in  very  small 
quantity  although  they  are  so  wide  spread.  Shepherd's  purse 
(Capsella  bursa-pastoris)  is  often  scarce  among  all  crops,  yellow 
toadflax  (Linaria  vulgaris)  is  rarely  or  never  dominant,  while 
the  curled  dock  (Rumex  crispus)  is  so  persistently  attacked 
that  it  is  rarely  allowed  to  take  first  place  among  the  weeds 
and  is  instead  often  reduced  to  a  position  of  scarcity. 

It  is  obvious  that  most  of  the  weeds  that  are  well 
distributed  among  all  crops  are  specially  adapted  for  the 
purpose,  being  able  to  tide  over  adverse  circumstances  in- 
duced by  the  habit  of  any  crop  or  by  any  particular  method 
of  cultivation.  Charlock,  shepherd's  purse,  curled  dock  and 
field  speedwell  produce  large  quantities  of  seeds  which  do  not 
all  germinate  at  the  same  time.  Some  of  these  seeds  start 
into  growth  and  the  seedlings  are  often  destroyed  by  cultiva- 
tion, but  another  batch  of  seeds  is  waiting  its  turn,  and 
usually  weeds  of  this  description  baffle  the  farmer  unless 
he  is  particularly  alert.  Creeping  thistle  and  bindweed  have 
creeping  underground  stems  which  possess  an  amazing  power 
of  retaining  their  vitality  and  growing  under  any  circum- 
stances, so  that  the  type  of  crop  does  not  affect  them  greatly. 
Corn  sow-thistle  and  groundsel  are  provided  with  plumed 
fruits,  and  the  seeds  may  not  only  remain  buried  in  the  soil 
from  one  year  to  another,  but  a  fresh  supply  may  be  constantly 


1 64  WEEDS  OF  FARM  LAND 

brought  by  the  wind,  throughout  the  year  in  the  case  of 
groundsel,  and  in  late  summer  and  early  autumn  in  the  case 
of  corn  sow-thistle. 

A  comparison  of  Table  I  with  Table  X  shows  that  very  few 
weeds  are  indifferent  both  in  regard  to  the  soil  they  occupy  and 
the  crops  amongst  which  they  grow,  shepherd's  purse,  creeping 
thistle,  curled  dock,  groundsel,  and  field  speedwell  being  the 
only  ones  in  this  category.  The  other  weeds  that  are  found  as 
often  in  one  crop  as  in  another  are  more  particular  as  to  soil,  so 
that  in  their  case  the  nature  of  the  soil,  and  not  that  of  the 
crop,  determines  the  distribution.  On  the  other  hand,  most  of 
the  weeds  that  have  no  preference  as  to  soil  are  greatly  in- 
fluenced by  the  nature  of  the  crop,  and  therefore  in  this  case 
the  crop,  and  not  the  soil,  is  the  determining  factor  in  dis- 
tribution. This  means  that  the  nature  of  the  soil  and  the 
type  of  crop  act  independently  on  the  weed  flora  and  that  the 
weeds  themselves  respond  in  various  ways  to  the  action  of 
the  two  factors  which  are  necessarily  at  work  at  one  and  the 
same  time. 

2.  (a)  Weeds  Specially  Associated  with  Root  Crops. — A 
careful  consideration  of  all  the  results  does  not  reveal  a  single 
weed  that  has  a  particular  association  with  root  crops.  Roots 
are  sown  quite  late  in  the  season,  which  gives  the  opportunity 
of  cleaning  the  land  well  beforehand.  During  the  growing 
season  the  cultivator  and  hoe  are  kept  at  work,  so  that  only 
the  most  persistent  and  ubiquitous  weeds  are  able  to  maintain 
a  footing. 

The  constant  cultivation  among  root  crops  tends  to  make 
a  great  clearance  of  the  weeds,  as  under  conditions  of  good 
farming  comparatively  few  plants  are  allowed  to  attain  any 
size.  In  this  way  the  abundance  of  the  weeds  is  greatly  re- 
duced, but  most  of  the  more  common  species  are  to  be  found 
among  the  roots  throughout  the  season.  This  is  because  the 
stores  of  seeds  or  underground  parts  in  the  soil  are  so  great 
that  the  very  cultivation  which  clears  away  one  crop  of  seed- 
lings prepares  the  soil  for  another  crop  to  germinate  or  start 
into  growth.  Some  weeds,  however,  seem  to  resent  the  inter- 
ference and  are  often  absent  from  roots  in  fields  that  they 
frequent  when  other  crops  occupy  the  ground. 


ARABLE  WEEDS.     ASSOCIATION  WITH  CROPS      165 

(b)    Weeds  Discouraged  by  Root  Crops. 

TABLE  XI.— WEEDS  DISCOURAGED  BY  ROOT  CROPS. 


Percentage  of  Frequency  (=  Number  of 

Times  Seen  per  100  Fields). 

Latin  Name. 

English  Name. 

o. 

j 

. 

• 

« 

s 

1 

1 

E 

O 

0 
O 

K 

! 

y 

Anagallis  ar  vends  . 

Pimpernel 

18 

21 

22 

22 

12 

19 

17 

Bartsia  odontites 

Red  bartsia 

7 

*4 

2 

5 

—  , 

8 

7 

Brassica  alba  . 

White  mustard 

7 

7 

8 

7 

2 

7 

7 

Cerastium  vulgatum 

Mouse-ear  chickweed 

7 

12 

2 

5 

I 

22 

5 

Euphorbia  exigua     . 

Dwarf  spurge  . 

ii 

13  * 

18 

12 

5 

12 

10 

Lychnis  vespertina  . 

Campion 

17 

12 

19 

21 

9 

37 

I4 

Papaver  rhozas 

Common  red  poppy 

33 

48 

38 

34 

13 

43 

26 

Plantago  major 

Greater  plantain 

19 

22 

24 

28 

8 

23 

22 

Ranunculus  repens    . 

Creeping  buttercup 

13 

17 

9 

13 

4 

23 

19 

Tussilago  farfara     . 

Coltsfoot 

20 

27 

19 

24 

12 

17 

26 

Viola  tricolor  . 

Pansy 

22 

25 

22 

19 

13 

35 

22 

Matricaria  inodora  . 

Scentless  mayweed 

16 

24 

13 

21 

8 

ii 

29 

Scandix  pec  ten 

Shepherd's  needle    . 

12 

22 

18 

15. 

3 

5 

10 

Very  few  of  those  weeds  thus  discouraged  are  present 
in  large  quantities  under  any  circumstances,  and  this  may 
account  for  the  comparative  ease  with  which  they  are  re- 
duced among  roots.  Pimpernel  (Anagallis  arvensis'),  mouse- 
ear  chickweed  (Cerastium  vulgatum),  and  dwarf  spurge 
(Euphorbia  exigua)  have  never  been  found  dominant  anywhere, 
while  greater  plantain  (Plantago  major),  creeping  buttercup 
(Ranunculus  repens],  field  pansy  ( Viola  tricolor],  campion 
(Lychnis  vespertina)  have  each  one  record  of  dominance  to 
their  credit  among  other  crops,  but  never  one  among  roots. 
The  red  poppy  (Papaver  rhceas),  however,  provides  a  single 
example  of  a  weed  that  is  most  abundant  in  some  districts, 
and  yet  often  absent  from  the  root  crops  in  these  very 
areas.  The  soil  contains  numberless  seeds,  but  under  these 
particular  conditions  of  cultivation  the  poppies  make  little  head- 
way. This  is  well  shown  by  the  fact  that  the  red  poppy  was 
only  once  found  dominant  amongst  roots,  when  among  other 
crops  in  the  same  district  it  dominated  no  less  than  92 
times.  This  fact  in  itself  shows  how  bitterly  the  poppy 
resents  the  interference  of  cultivation.  White  mustard  (Bras- 
alba) behaves  in  a  similar  way,  though  the  discrepancy 


1 66  WEEDS  OF  FARM  LAND 

is  less  marked — with  two  instances  of  dominance  among  roots 
and  twenty-three  elsewhere.  Coltsfoot  (Tussilago  farfara)  is 
very  considerably  affected,  but  makes  a  better  fight  for  its 
position  than  any  other  weed  in  the  group,  managing  to 
become  dominant  as  often  in  proportion  among  roots  as 
among  other  crops. 

(3)  (#)    Weeds  Specially  Associated  with  Temporary  Grass  and 
Clover  ("  Seeds")  or  with  "  Seeds"  and  Wheat  Crops. 

These  two  classes  of  weeds  are  very  clearly  marked  out. 
Two  distinct  factors  are  evident  in  this  case,  which  work  to- 
gether and  help  to  make  the  flora  of  "seeds"  crops  more 
distinctive  than  any  other.  The  first  factor  is  that  "  seeds  " 
form  essentially  .a  smothering  crop.  They  are  sown  very 
thickly,  and  from  an  early  date  they  spread  out  and  cover  the 
ground  closely,  in  contrast  to  the  cereals,  which  grow  fairly 
upright,  and  to  roots,  in  which  open  spaces  are  left  for  a  long 
period  of  time.  Consequently,  any  weeds  that  dislike  com- 
petition stand  a  poor  chance  among  seeds,  and  only  those  can 
flourish  whose  habit  permits  them  to  enter  into  effective  com- 
petition with  the  crop.  Some,  but  not  all,  of  the  "  seeds  "  weeds 
are  equally  abundant  among  wheat.  The  second  factor  is  that 
the  seed  of  clover,  trefoil,  medick,  etc.,  is  so  small  that  effec- 
tive cleaning  is  difficult,  and  large  numbers  of  weed  seeds 
may  therefore  be  introduced  when  the  crop  is  sown.  These 
introduced  weeds  are  a  class  apart,  for  they  flourish  among 
their  harbouring  crop,  but  do  not  persist  further  on  in  the 
rotation  in  any  quantity.  Apparently  cultivation  is  obnoxious 
to  them,  and  the  great  majority  quietly  disappear  when  once 
the  ley  is  ploughed  up.  The  weeds  that  are  common  among 
both  seeds  and  wheat  are  also  usually  introduced  with  the 
seed  crop,  but  they  seem  to  be  able  to  hold  their  ground 
for  a  season  in  the  wheat  that  so  commonly  follows  a  clover 
ley.  After  this,  however,  they  tend  to  disappear  like  the  rest. 
The  two  sets  of  weeds  are  as  follows  : — 


ARABLE  WEEDS.     ASSOCIATION  WITH  CROPS      167 


(a)    Weeds  Specially  Associated  with  Temporary  Grass  or 
Clover  ("Seeds"). 

TABLE  XII.— WEEDS  SPECIALLY  ASSOCIATED  WITH  TEMPORARY 
GRASS  OR  CLOVER. 


Percentage  of  Frequency  (=  Number  of 

Times  Seen  per  100  Fields). 

Latin  Name. 

English  Name. 

a 

.j 

. 

. 

. 

la 

o 

3 

•n 

rt 

2 

"S 

ss 

9 

* 

CQ 

M 

09 

SM 

Anthemis  arvensis 

Corn  chamomile 

3 

4 

2 

2 

o-5 

12 

Daucus  carota    . 

Wild  carrot   . 

3 

2 

5 

I 

I 

17 

5 

Geranium  molle  . 

Dove's-foot  crane'  -bill 

8 

£j 

4 

O'C 

5 

31 

2 

Lychnis  vespertina 
Plantago  lanceolata 

Campion 
Ribwort  plantain 

9 

12 

7 

19 

2 

21 

4 

9 

2 

37 
41 

14 

9 

Sheradia  arvensis 

Field  madder 

7 

8 

I 

5 

5 

31 

5 

Viola  tricolor 

Pansy    . 

22 

25 

22 

19 

35 

22 

Although  these  weeds  are  so  usually  found  among  seeds 
they  are  very  seldom  dominant,  probably  because  the 
smothering  nature  of  the  crop  prevents  any  other  plant  from 
usurping  too  predominant  a  position.  Most  of  the  plants  are 
very  closely  connected  with  "  seeds"  crops  only,  but  campion 
(Lychnis  vespertina)  and  field  pansy  ( Viola  tricolor)  are 
common  among  others,  with  a  decided  preference  for  "  seeds  ". 
Both  these  weeds  are  introduced  with  "  seeds,"  and  they  are 
able  to  hold  their  own  throughout  the  rotation,  though 
never  present  in  any  quantity.  Campion  (Lychnis  vesper- 
tina) is  a  great  contrast  to  its  companion,  as  its  habit  is  so 
utterly  different.  Most  of  this  section  are  small  low  growing 
plants  which  spread  out  close  to  the  surface  ofthe  ground  in  a 
rosette  form,  so  that  no  other  plant  is  able  to  crowd  into  the 
ground  occupied  by  the  spreading  of  the  weed.  Campion, 
however,  is  a  bold,  strong  grower,  and  shoots  up  over  the 
head  of  the  crop  to  revel  in  the  freedom  of  the  upper  air. 

In  addition  to  the  weeds  given  in  Table  XII  a  number  of 
others  that  occur  comparatively  seldom  are  chiefly  associated 
with  "seeds"  crops.  These  all  behave  in  the  same  way,  and 
disappear  with  the  succeeding  crop  in  the  rotation. 

The  chief  of  these  are  : — 


Carduus  nutans . 
Cirsium  lanceolatum 
Filago  germanica 
Geranium  dissectum 
Geranium  pusillum 
Reseda  lutea 


Musk  thistle 

Spear  thistle 

Cudweed 

Cut-leaved  geranium 

Small -flowered  crane's-bill 

Wild  mignonette  (equally  common  among  barley). 


i68 


WEEDS  OF  FARM  LAND 


(/3)    Weeds  Specially  Associated  with    Wheat  and  Temporary 
Grass  and  Clover  ("  Seeds  "). 

TABLE  XIII.— WEEDS  SPECIALLY  ASSOCIATED  WITH  WHEAT  AND 
TEMPORARY  GRASS  AND  CLOVER. 


Percentage  of  Frequency  (-  Number  of 
Times  Seen  per  100  Fields). 

Latin  Name. 

English  Name. 

| 

. 

frf 

0 
< 

1 

£ 

1 

• 

o 

1 

& 

J« 

Alchemilla  arvensis    . 

Lady's  mantle 

9 

23 

I 

5 

o'5 

16 

2 

Arenaria  serpyllifolia 

Thyme-leaved  sandwort 

10 

13 

4 

4 

4 

32 

5 

Cerastium  vulgatum  . 

Mouse-ear  chickweed    . 

7 

12 

2 

5 

I 

22 

5 

Myosotis  arvensis 

Field  forget-me-not 

15 

25 

7 

12 

7 

33 

19 

Veronica  arvensis 

Wall  speedwell      . 

•7 

20 

i 

4 

o'5 

IO 

7 

These  weeds  resemble  the  others  associated  with  "seeds" 
crops  in  that  they  are  seldom  or  never  dominant.  Most  of 
them  are  so  small  and  inconspicuous  that  care  has  to  be  taken 
in  field  work  to  give  them  their  due  weight  of  importance,  as 
it  is  easy  to  under-estimate  the  quantity  present.  Sandwort 
(Arenaria  serpyllifolia),  mouse- ear  chickweed  (Cerastium 
vulgatmri),  and  forget-me-not  (Myosotis  arvensis}  occur  more 
frequently  among  seeds  than  among  wheat,  whereas  lady's 
mantle  (Alchemilla  arvensis)  and  wall  speedwell  (Veronica 
arvensis)  exhibit  a  greater  preference  for  wheat.  All  of  them 
are  relatively  seldom  seen  among  any  other  crops. 

(b)    Weeds  Discouraged  by  "Seeds"   Crops. 

It  has  already  been  mentioned  that  the  peculiar  habit  of 
"  seeds  "  crops  is  detrimental  to  the  growth  of  many  weeds. 
Some  of  the  commonest  and  most  abundant  farm  weeds,  in- 
cluding several  that  are  utterly  indifferent  to  the  nature  of 
the  soil  they  frequent,  cannot  endure  the  close  competition  of 
"seeds,"  and  refuse  to  grow  among  them.  The  seeds  and 
underground  parts  of  the  weeds,  perhaps  after  making  a  few 
futile  efforts  to  establish  a  position,  simply  remain  dormant  in 
the  soil  until  such  time  as  the  antagonistic  crop  is  removed 
and  more  favourable  conditions  supervene.  Then,  little  the 
worse  for  their  waiting  period,  they  reassert  themselves  among 
the  later  crops  in  the  rotation. 


ARABLE  WEEDS.     ASSOCIATION  WITH  CROPS      169 
TABLE  XIV.— WEEDS  DISCOURAGED  BY  "  SEEDS  "  CROPS. 


Percentage  of  Frequency  (=  Number  of 

Times  Seen  per  100  Fields). 

Latin  Name. 

English  Name. 

A  11 

Peas 

All 

Crops. 

Wheat. 

Barley. 

Oats. 

Roots. 

Seeds. 

and 
Beans. 

Agropyron   repens  . 

Couch-grass 

15 

18 

5 

12 

25 

4 

24 

Agrostis  spp>  . 

Bent-grass 

22 

33 

IO 

18 

28 

14 

29 

A  trip  lex  patula 

Orache      . 

15 

16 

9 

18 

23 

3 

16 

Chenopodium  album 

Fat  hen     . 

44 

32 

61 

48 

60 

17 

48 

Equisetum  arvense 

Horsetail  . 

24 

29 

26 

26 

24 

14 

31 

Galium  aparine 

Goosegrass 

25 

37 

21 

21 

23 

15 

38 

Lamium  purpureum 

Red  deadnettle 

4 

3 

2 

3 

6 

I 

3 

Mentha  arvensis     . 

Corn  mint 

14 

17 

16 

12 

14 

8 

17 

Poa  annua 

Annual  meadow-grass 

17 

35 

10 

*4 

J4 

8 

17 

Polygonum  aviciilare 

Knotgrass 

56 

62 

58 

63 

64 

21 

62 

Poly  go  num  con-volvulus 

Black  bindweed 

49 

48 

64 

56 

63 

2O 

45 

Polygonum  persecaria 

Willow-weed    . 

12 

10 

12 

18 

15 

3 

10 

Spergula  arvensis  . 

Spurry 

19 

13 

J7 

34 

23 

7 

24 

Stellaria  media 

Chickweed 

45 

52 

45 

4i 

59 

18 

50 

Veronica  hcdercefolia 

Ivy-leaved  speedwell 

18 

20 

22 

20 

21 

2 

29 

Veronica  tournefortii 

Large  field  speedwell 

29 

31 

19 

22 

36 

14 

40 

All  the  weeds  classified  in  the  above  table  are  seriously 
handicapped  in  the  presence  of  a  "seeds"  crop,  but  some  are 
much  more  affected  by  the  competition  than  others.  Bent 
grass  (Agrostis  spp.},  horsetail  (Equisetum  arvense},  goosegrass 
(Galium  aparine],  corn  mint  (Mentha  arvensis),  and  large  field 
speedwell  (Veronica  tournefortii}  are  among  those  that  are 
less  influenced.  Orache  (A  triplex  patula},  knotgrass  (Poly- 
gonum aviculare},  willow-weed  (Polygonum  persecaria},  and 
especially  ivy-leaved  speedwell  (Veronica  hedercefolia}  are 
more  seriously  affected,  as  their  frequency  is  far  less  than  half 
that  among  all  crops.  Couch-grass  (Agropyron  repens}  appears 
to  come  in  this  latter  group,  but  it  is  quite  conceivable  that  on 
some  occasions  it  was  overlooked,  as  it  is  difficult  to  dis- 
tinguish it  from  some  of  the  grasses  which  have  a  legitimate 
place  in  "  seeds  "  crops. 

The  majority  of  these  weeds  are  rarely  present  in  any 
quantity,  and  few  of  them  are  ever  dominant  Orache,  goose- 
grass,  red  dead  nettle,  corn  mint,  willow-weed,  chickweed, 
couch-grass  and  ivy-leaved  speedwell  were  never  observed 
to  be  dominant  among  this  crop  throughout  the  course  of  the 
investigation,  though  many  of  them  were  frequently  the  chief 
weeds  among  other  crops.  Bent-grass,  fat  hen,  horsetail, 


170 


WEEDS  OF  FARM  LAND 


annual  meadow-grass,  knotgrass,  black  bindweed,  spurry,  and 
large  field  speedwell  were  very  occasionally  found  dominant, 
but  much  less  frequently  than  they  were  in  other  cases. 

4.   (a)    Weeds  Specially  Associated  with  Peas  and  Beans. 

In  spite  of  the  difference  in  soil  conditions  under  which 
peas  and  beans  are  grown  they  carry  a  very  similar  weed  flora. 
These  crops  are  different  in  habit  from  any  others  grown  on  a 
farm  ;  the  individual  plants  are  very  strong  growing,  but  in 
the  earlier  stages  they  do  not  cover  the  ground  to  the  same 
extent  as  a  young,  healthy  crop  of  seeds.  Later  on  in  life 
peas  and  beans  are  as  efficient  smother  crops  as  are  seeds,  but 
the  diversity  of  their  earlier  history  influences  the  weed  flora 
considerably,  so  that  the  plants  that  are  encouraged  or  injured 
by  the  two  classes  of  crops  are  entirely  different.  Peas  and 
beans  are  regarded  as  being  the  dirtiest  crops  on  a  farm, 
because  the  weeds  have  a  fair  opportunity  of  establishing  them- 
selves while  the  crop  is  young  ;  little  cultivation  can  be  carried 
out  for  fear  of  damaging  the  peas  and  beans,  and  many  of  the 
weeds  thus  become  strong  enough  to  withstand  the  later 
smothering  action.  Only  two  weeds,  black  bent  and  corn 
buttercup,  receive  special  encouragement  from  this  type  of 
crop,  and  both  these  are  correspondingly  prevalent  among 
wheat,  and  are  discussed  under  that  heading  also. 

TABLE  XV.— WEEDS  SPECIALLY  ASSOCIATED  WITH  PEAS  AND  BEANS. 


Latin  Name. 

English  Name. 

Percentage  of  Frequency  (=  Number  of 
Times  Seen  per  100  Fields). 

All 
Crops. 

Wheat. 

Barley. 

Oats. 

,Roots. 

Seeds. 

Peas 
and 
Beans. 

Alopecurus  agrestis    . 
Ranunculus  arvensis  . 

Black  bent 
Corn  buttercup  . 

5 
4 

9 
12 

2 
2 

4 
3 

2 

I 

3 

i 

21 

7 

Black  bent  (Alopecurus  agrestis)  is  profoundly  influenced 
by  cultivation.  If  once  it  gets  a  fair  start  and  is  not  interfered 
with  too  much  it  can  hold  its  own  well,  but  if  badly  dis- 
turbed in  the  early  stages  it  has  very  little  chance.  For  this 
reason  it  is  not  usually  a  serious  pest,  ordinary  rotation 
farming  keeping  it  in  check.  Peas  and  beans  afford  a  most 
congenial  shelter  for  it,  the  comparative  openness  of  situation 
at  the  outset  and  the  subsequent  lack  of  cultivation  providing 


ARABLE  WEEDS.     ASSOCIATION  WITH  CROPS      171 


the  very  conditions  it  delights  in,  so  that  the  black  bent  is  able 
to  make  good  growth  before  the  crop  gets  too  thick,  and  is  then 
strong  enough  to  grow  up  with  the  peas  and  beans  and  to 
maintain  its  position. 

(b)    Weeds  Discouraged  by  Peas  and  Beans. 

TABLE  XVI.— WEEDS  DISCOURAGED  BY  PEAS  AND  BEANS. 


Latin  Name. 

English  Name. 

Percentage  of  Frequency  (=  Number  of 
Times  Seen  per  100  Fields). 

All 
Crops. 

Wheat. 

Barley. 

Oats. 

Roots. 

Seeds. 

Peas 
and 
Beans. 

Centaur  ea  nigra 
Euphorbia  helioscopia 
Potentilla  anserina    . 

Hardhead  . 
Sun  spurge    /    . 
Silverweed 

6 

10 

6 
12 

9 
13 
12 

6 
6 

10 

6 

8 

6 
5 
14 

2 

Scabiosa  arvensis 
Silene  inflata 
Taraxacum  vulgare  . 

Field  scabious    . 
Bladder  campion 
Dandelion  . 

ii 
9 
9 

12 

9 
10 

15 
16 

9 

13 
8 
10 

6 
4 
3 

*4 
ii 

15 

3 
3 
3 

Fumaria  officinalis    . 

Fumitory  . 

21 

19 

24 

26 

25 

H 

12 

This  is  not  a  very  well-marked  class  of  plants.  With  the 
exception  of  fumitory  (Fumaria  officinalis)  few  of  the  weeds 
are  very  frequent  or  plentiful,  and  several  of  them  are  ad- 
versely affected  by  other  crops  as  well  as  by  peas  and  beans. 

Hardhead  (Centaur ea  nigra)  and  sun  spurge  (Euphorbia 
helioscopia)  are  the  most  influenced  by  this  crop,  as  they  failed 
to  appear  among  it  on  any  occasion,  though  they  were  well 
distributed  through  all  other  crops.  Neither  of  these  weeds 
is  ever  dominant,  and  sun  spurge  is  frequently  scarce,  so  it  is 
easy  to  understand  why  they  disappear  rapidly  under  unfavour- 
able circumstances.  Silverweed  (Potentilla  anserina)  is  nearly 
as  intolerant  as  the  last  two  described,  for  it  was  only  twice 
seen  among  peas  or  beans. 

Field  scabious  (Scabiosa  arvensis),  bladder  campion  (Silene 
inflata)  and  dandelion  (Taraxacum  vulgare)  have  almost  as 
great  an  objection  to  root  crops  as  to  peas  and  beans.  Although 
they  occur  rather  frequently  they  are  seldom  or  never  dominant, 
and  dandelion  is  often  scarce. 

Fumitory  (Fumaria  officinalis)  is  abundant  and  frequent. 
It  is  an  early  plant  and  much  of  it  has  died  away  by  June  and 
July,  so  that  quite  possibly  it  is  really  more  abundant  than 
the  records  show,  as  the  observations  made  later  in  the  year 


172  WEEDS  OF  FARM  LAND 

may  have  often  failed  to  take  adequate  account  of  the  species. 
It  does  not  show  a  very  pronounced  objection  to  growing 
among  any  crop,  but  "  seeds,"  peas,  and  beans  reduce  it  by 
about  one-half.  The  quantity  occurring  is  reduced  even  more 
than  the  frequency,  for  although  fumitory  is  very  often 
dominant  among  most  crops  at  certain  periods  of  the  year,  it 
was  only  once  observed  dominant  among  peas  and  beans. 
Usually  this  plant  gives  very  little  trouble,  as  it  is  ephemeral 
and  the  quantity  is  not  often  serious  even  when  it  is  the  chief 
weed  in  a  field. 

Association    of   Weeds   with    Cereal   Crops. 

The  cereals  form  a  group  of  plants  that  collectively  has 
less  direct  influence  upon  the  weed  flora  than  any  of  the  other 
types  of  crop.  The  drills  are  placed  some  distance  apart  and 
the  habit  of  the  young  plant  is  such  that  the  weed  seeds  have 
a  good  opportunity  of  starting  into  growth  under  favourable 
conditions.  Later  cultivation,  where  this  is  done,  destroys 
many  of  the  weeds,  but  those  that  are  present  along  the  drills 
themselves  escape  destruction.  Consequently,  the  weed  flora 
of  cereal  crops  remains  fairly  representative,  except  where 
the  crop  is  so  exceptionally  heavy  that  all  undergrowth  is 
smothered  out.  Arable  weeds  occur  with  almost  equal  fre- 
quency among  cereals  and  among  all  crops  added  together, 
and  in  most  cases  the  figures  practically  coincide.  A  few 
weeds  are  rather  more  frequent  among  cereals,  as  is  shown  in 
the  table  on  opposite  page,  but  even  with  these  the  differences 
are  not  great.  Only  two  weeds,  ribwort  plantain  (Plantago 
lanceolata)  and  dove's-foot  crane's-bill  (Geranium  molle),  are 
less  frequent,  but  this  is  not  due  to  discouragement  by  the 
cereal  crop,  but  to  their  introduction  in  large  quantities  in  the 
seeds  of  temporary  leys. 

The  weed  floras  associated  with  the  individual  cereal  crops 
show  certain  variations,  but  these  differences  are  not  at  all 
clearly  marked.  Every  weed  of  any  importance  is  found 
amongst  all  the  cereals,  but  some  are  more  particularly  encour- 
aged or  discouraged  by  one  or  other  of  them.  Only  two 
weeds  are  so  adversely  affected  by  any  cereal  crop  that  they 
practically  disappear — i.e.  lady's  mantle  (Alchemilla  arvensis) 
and  wall  speedwell  (  Veronica  arvensis),  which  are  hardly  ever 
seen  among  barley.  In  all  other  cases  the  association  is  less 
definite.  Some  of  the  weeds  can  be  grouped  in  two  distinct 
ways,  according  as  they  are  more  particularly  associated  with 


ARABLE  WEEDS.     ASSOCIATION  WITH  CROPS      173 
WEEDS  THAT  ARE  MORE  FREQUENT  IN  CEREAL  CROPS. 


Latin  Name. 

English  Name. 

Percentage  of  Frequency 
(=  Number  of  Times  Seen 
per  100  Fields). 

All  Crops. 

Cereal  Crops. 

Anagallis  arvensis 
Brassica  sinapis 
Papaver  rhceas 
Plantago  major 
Polygonum  convolvulus 
Scandix  pecten 
Veronica  agrcstis 

Scarlet  pimpernel 
Charlock     . 
Red  poppy 
Greater  plantain 
Black  bindweed 
Shepherd's  needle 
Field  speedwell  . 

18     . 
34 
33 
19 
49 

12 
19 

22 

41 
41 
24 

56 
19 
25 

Weeds  that  are  Less  Frequent  in  Cereal  Crops. 

Geranium  mollc 
Plantago  lanccolata 

Dove's-foot  crane's-bill 
Ribwort  plantain 

7'5 

9 

3 
5 

wheat  or  are  relatively  scarce  among  barley.  The  two  groups, 
however,  are  largely  identical,  indicating  that  some  factor  is 
at  work  with  one  crop  that  is  absent  from  the  other.  This 
factor  is  probably  the  difference  in  the  time  of  sowing  of  the 
two  crops.  Wheat  in  this  country  is  usually  sown  in  the 
autumn,  thus  hindering  an  effective  cleaning  of  the  land. 
Weed  seeds  germinate  and  grow  up  with  the  corn,  and  the 
nature  of  the  crop  hinders  an  effective  clearance  by  later 
cultivation.  Barley,  on  the  other  hand,  is  spring  sown,  very 
often  after  roots.  The  land  is  ploughed  up  and  lies  fallow 
throughout  the  winter,  when  the  weed  seeds  germinate  and 
make  good  headway.  Further  cultivation  occurs  before  the 
crop  is  sown,  the  weed  seedlings  are  destroyed,  and  even 
though  other  dormant  seeds  may  start  into  growth  they  have 
to  face  far  greater  competition  from  the  crop,  which  gets 
away  rapidly  and  is  a  much  greater  competitor  to  the  young 
seedlings  than  is  the  wheat  plant  to  those  weeds  that  germinate 
in  autumn.  If  all  these  weeds  are  cut  out,  very  few  are  left 
which  show  any  special  connection  with  particular  cereals. 
In  the  following  table  the  two  groups  are  put  together  in  so 
far  as  they  are  identical,  and  the  remaining  weeds  are  classified 
under  their  separate  headings.  It  may  be  noted  that  while 
spurry  (Spergula  arvensis]  and  fat  hen  (Chenopodium  album) 
are  both  discouraged  by  wheat,  the  former  is  specially  prevalent 
among  oats  and  the  latter  among  barley. 


174 


WEEDS  OF  FARM  LAND 


Latin  Name. 

English]  Name. 

Percentage  of  Frequency 
(=  Number  of  Times  Seen 
per  100  Fields). 

i      All         w. 
Cereals.     Wh 

eat.     Barley. 

Weeds  that  are  Specially  Frequent  among  Wheat  and  Less  Frequent 

among  Barley. 

Agrostis  spp.     . 

Bent  grass 

23              3 

3             10 

Alchemilla  arvensis  . 

Lady's  mantle 

II              2 

3              i 

Bartsia  odontites 

Red  bartsia     . 

8            i 

4             2 

Cerastium  vulgatum 

Mouse-ear  chickweed 

7            i 

2                 2 

Myosotis  arvensis 

Field  forget-me-not 

16            2 

5             7 

Poa  annua 

Annual  meadow-grass    . 

21                3 

5           TO 

Ranunculus  arvensis 

Corn  buttercup 

6            i 

2                 2 

Veronica  arvensis 

Wall  speedwell       . 

IO                 2 

O                 I 

I 

Weeds  Specially  Frequent  Among  Wheat. 

All  Cereals. 

Wheat,. 

Alopecurus  agrestis  . 

Black  bent     . 

5 

9 

Arenaria  serpyllifolia 

Thyme-leaved  sandwort 

8 

13 

Galium  apanne 

Goosegrass    ...            27 

37 

Weeds  Less  Frequent  Among  Wheat. 

Chenopodium  album 

Fat  hen 

45 

32 

Spergula  arvensis     . 

Spurry    .... 

20 

13 

Weeds  Specially  Frequent  among  Barley. 

All  Cereals. 

Barley. 

Chenopodium  album 

Fat  hen 

45 

6l 

Euphorbia  helioscopia 

Sun  spurge     . 

8 

13 

Silene  injlata  . 

Bladder  campion    . 

9 

16 

Weeds  Less  Frequent  among  Barley. 

Agropyron  repens 
Matricaria  inodora  . 

Couch  grass  . 
Scentless  mayweed 

12 
2O 

5 
13 

Sheradia  arvensis 

Field  madder 

5 

I 

Weeds  Specially  Frequent  among  Oats. 

All  Cereals  . 

Oats. 

Rumex  acctosella 

Sheep's  sorrel 

8 

15 

Spergula  arvensis     . 

Spurry   .... 

20 

34 

Weeds  Less  Frequent  among  Oats. 

Geranium  molle 

Dove's-foot  crane's-bill  . 

3 

0'5 

Veronica  arvensis 

Wall  speedwell      . 

IO 

4 

CHAPTER  XL 

GRASS-LAND  WEEDS. 

THE  consideration  of  the  weeds  of  grass-land  presents  a  very 
different  problem  from  that  of  arable  weeds  because  of  the 
totally  different  nature  of  the  crop  with  which  the  weeds  are 
associated.  Arable  land  crops  are,  so  to  speak,  alien  to  their 
situation  and  are  grown  on  bare  soil,  which  offers  a  clear 
field  for  the  competition  of  other  species  that  are  native  to  the 
soil  and  would  carry  all  before  them  if  they  were  not  hindered 
by  cultivation.  On  grass-land,  on  the  contrary,  the  crop  con- 
sists of  an  association  of  plants  that  are  usually  themselves 
native  to  the  soil  and  that  grow  in  a  closely  interwoven  mat 
covering  the  surface  of  the  ground,  thus  excluding  all  plants 
that  cannot  make  headway  against  keen  competition.  Then 
again,  on  arable  land  it  is  only  the  produce  of  the  sown  seed 
that  is  of  use  as  a  crop,  whereas  on  grass-land  it  matters  little 
what  particular  species  enter  into  the  composition  of  the 
herbage  provided  that  they  are  not  injurious  or  poisonous  and 
that  the  feeding  value  for  stock  is  high.  Consequently  in 
many  cases  it  is  not  possible  to  draw  a  sharp  distinction  be- 
tween the  crop  plants  and  the  weeds,  as  a  species  that  is  quite 
a  useful  constituent  of  herbage  in  one  place  may  be  a  veritable 
pest  elsewhere.  Whether  it  be  mown  for  hay  or  grazed, 
herbage  typically  consists  of  a  mixture  of  grasses,  leguminous 
plants,  and  miscellaneous  species  from  other  orders.  Each  of 
these  groups  contains  some  plants  that  are  most  valuable  from 
the  farmer's  point  of  view  but  others  that  are  regarded  as 
of  little  use  or  as  harmful  weeds.  The  criterion  is  usually 
the  feeding  value  of  the  plant  but  this  varies  with  circum- 
stances, as  it  is  influenced  by  soil  conditions,  climate,  and 
other  factors,  concerning  which  our  knowledge  is  very  imper- 
fect. For  instance,  on  Romney  Marsh 1  adjacent  fields  are 

1  Hall,  A.  D.,  and  Russell,  E.  J.  (1911),  "A  Report  on  the  Agriculture  and 
Soils  of  Kent,  Surrey,  and  Sussex,"  p.  60. 

175 


176  WEEDS  OF  FARM  LAND 

sometimes  "  fatting"  and  " non-fatting,"  i.e.  while  the  former 
is  excellent  grazing  pasture  and  fattens  sheep  rapidly  the 
latter-is  of  little  use  except  for  carrying  store  beasts.  A  com- 
plete botanical  analysis  of  the  herbage  reveals  no  variation  in 
the  species  present  that  would  account  for  such  a  difference, 
so  that  the  same  combination  of  plants  is  far  more  valuable 
in  the  one  case  than  in  the  other.  Some  grasses,  as  Yorkshire 
fog  and  tall  oat,  tend  to  grow  rank  and  coarse  under  favour- 
able conditions  and  are  then  rightly  considered  as  weeds,  but 
nevertheless  the  best  pastures  and  meadowland  of  the  highest 
feeding  value  usually  contain  one  or  both  of  these  grasses,  the 
proportion  of  Yorkshire  fog  often  being  quite  appreciable. 

On  account  of  this  necessary  reservation,  therefore,  a  weed 
of  grass-land  may  be  considered  to  be  any  plant  that  is  in 
itself  useless  or  injurious  (a  mere  cumberer  of  the  ground),  or 
any  plant  that  in  the  case  in  question  is  of  low  feeding  value 
and  by  its  abundance  or  rank  growth  tends  to  crowd  out  and 
supplant  other  species  that  under  the  same  circumstances 
would  provide  far  more  nourishment  to  the  stock  feeding 
thereon.  As  high  feeding  value  is  more  usually  associated 
with  certain  grasses  and  leguminous  plants  than  with  miscel- 
laneous species,  it  often  happens  that  the  most  valuable 
pastures  and  meadows  are  stocked  almost  entirely  with  the 
former  while  the  inferior  grass-lands  show  a  large  percentage 
of  the  latter  in  the  composition  of  their  herbage.1  As  a  matter 
of  fact,  it  is  usually  fairly  easy  to  decide  whether  a  certain 
species  is  to  be  considered  as  a  weed  or  as  a  useful  plant  on  a 
particular  area  of  grass-land.  Various  rank  and  tall-growing 
plants,  as  thistles,  woodwax,  nettles,  chervil  and  docks,  do  not 
under  any  circumstances  enter  into  the  legitimate  composition 
of  the  herbage  and  are  always  to  be  regarded  as  weeds.  Run- 
ning plants,  such  as  couch-grass  (Agropyron  repens],  creeping 
buttercup  (Ranunculus  repens),  bindweed  (Convolvulus  arvensis), 
and  bent  grass  (Agrostis  spp.},  which  tend  to  cover  large  areas 
of  ground  with  their  matted  stems  and  roots,  do  much  damage 
to  grass-land,  and  certain  rosette  plants  that  lie  very  close  to  the 
ground,  e.g.  mouse-ear  hawk  weed  (Hieracium  pzlosella),  suffo- 
cate all  other  plants  growing  under  the  spread  of  their  leaves. 
All  these  must  be  regarded  as  pernicious  and  to  be  removed 
whenever  possible.  Poisonous  or  injurious  plants,  such  as 
meadow  saffron,  purging  flax,  hemlock,  and  garlic,  are  not  to  be 

1  Armstrong,  S.  F.  (1907),  "  Botanical  and  Chemical  Composition  of  the 
Herbage  of  Pastures  and  Meadows,"  Jour.  Agric.  Sci.,  II,  pp.  283-304. 


GRASS-LAND  WEEDS  177 

tolerated,  and  come  into  the  weed  category.  The  classification 
of  many  other  plants,  as  described  above,  depends  upon 
circumstances. 

Local  conditions,  often  varying  within  small  areas,  do 
much  to  determine  the  relative  abundance  of  grass-land  weeds. 
The  amount  of  water  in  the  soil  is  a  most  potent  factor  in  this 
way,  and  its  action  is  well  seen  on  low-lying  fields  where  the 
water  table  approaches  the  surface  of  the  soil  rather  nearly, 
as  happens  in  alluvial  areas  (cf.  Berkeley  district.  Gloucester- 
shire, and  Sedgemoor,  Somerset).  These  fields  are  often 
thrown  into  ridge  and  furrow,  the  survivals  of  old  arable 
cultivation,  and  in  the  furrow  where  water-logging  occurs 
rushes  and  other  moisture-loving  plants  abound.  Up  the 
sides  of  the  ridges  the  rushes  gradually  get  fewer  as  the  soil  be- 
comes slightly  drier,  and  unless  the  field  is  abnormally  low-lying 
and  damp  the  tops  of  the  ridges  are  free  from  rushes.  Coin- 
cidently  with  the  dying  out  of  the  rushes  there  is  often  an  in- 
coming of  the  tall  buttercup  (Ranunculus  acris\  which  likes  a 
considerable  degree  of  moisture  but  cannot  withstand  absolute 
waterlogging,  so  that  the  tops  of  the  ridges,  though  bare  of 
rushes,  are  often  colonised  by  masses  of  these  buttercups.  A 
further  sequence  may  be  observed  where  the  fields  are  slightly 
higher  and  but  little  waterlogging  occurs  even  in  the  furrows. 
Then  the  rushes  get  less  and  eventually  die  out,  the  tall  butter- 
cup descends  from  the  ridge  into  the  furrow,  and  is  replaced 
more  or  less  completely  on  the  top  of  the  ridge  by  the  allied 
bulbous  buttercup  (R.  bulbosus\  which  is  even  more  impatient 
of  an  excess  of  water.  The  above  illustrates  what  is  often  seen 
in  the  West  Country,  but  with  possible  variation  in  the  plants 
concerned  it  gives  a  good  picture  of  what  may  be  expected  to 
occur  in  any  locality  when  excess  of  water  is  present.  Drain- 
ing gullies  and  depressions  in  grass  fields  are  often  colonised 
by  various  species  of  docks.  The  broad-leaved  dock  (Rumex 
obtusifolius}  tends  to  congregate  in  places  where  the  water 
spreads  out  to  flood  the  fields,  while  the  sharp  dock  (R.  con- 
glomerates] and  the  blood-red  dock  (£.  sanguineus)  frequent 
the  gullies  and  shady  places  and  the  edges  of  fields. 

Where  the  water  supply  is  particularly  abundant,  as  on 
peaty  soils,  the  herbage  takes  on  quite  a  different  character 
from  that  found  in  drier  situations  as  the  typical  grass-land 
plants  are  less  plentiful,  their  place  being  taken  by  a  number 
of  miscellaneous  plants  usually  regarded  as  weeds  of  low 
nutritive  value,  such  as  ragged  robin,  meadowsweet,  cotton 

12 


178  WEEDS  OF  FARM  LAND 

grass,  creeping  jenny,  mint,  sedge  and  marsh  bedstraw.  If 
still  more  water  is  present  the  change  is  yet  greater,  and  true 
water  and  marsh  plants  appear,  including  marsh  marigold, 
arrowhead,  lady's  smock,  watercress,  pennywort,  and  purple 
loosestrife,  in  addition  to  various  species  of  rushes. 

A  great  contrast  to  the  weed  flora  of  damp  land  is  seen 
in  that  of  well-drained  high  grass-land.  The  grasses,  instead 
of  being  lush  and  rank,  tend  to  grow  small  and  fine,  and  such 
weeds  as  daisy,  dog  daisy,  yellow  rattle,  pignut,  sorrel,  quaker 
grass  and  rough  brome  are  often  abundant.  Poor  pastures  on 
dry  land  are  frequently  characterised  by  such  weeds  as  milk- 
wort  (Polygala  vulgaris)  hardhead,  beaked  hawksbeard  (Crepis 
taraxacifolia\  salad  burnet  (Poterium  sanguisorbd),  thyme, 
lady's  mantle  (Alchemilla  vulgaris),  and  ragwort,  while  such 
worthless  grasses  as  false  brome  (Brachypodium  pinnatutn  and 
B.  sylvaticum)  and  soft  brome  (Bromus  mollis)  are  frequently 
present.1 

Although  it  is  not  always  possible  to  fix  the  status  of  a 
plant  as  being  useful  or  useless  on  grass-land,  it  may  be  per- 
missible to  make  a  rough  classification  as  follows  : — 

A.  PLANTS  THAT  MUST  BE  REGARDED  AS  WEEDS  UNDER 
ALL  CIRCUMSTANCES. 

(a)  Poisonous  and  Injurious  Plants. 

Autumn  crocus  (Colchicwn  autumnale). 

Bindweed  (Convolvulus  arvensis). 

Buttercup  (Ranunculus  spp.). 

Crow  garlic  (Allium  vineale). 

Horsetail  (Equisetum  spp.). 

Huffcaps  (Air a  ccespitosa). 

Purging  flax  (Linum  catharticum). 

Ragwort  (Senecio  jacobaa). 

Ramsons  (Allium  ursinum). 

Wild  barley  (Hordeum  pratense). 

All  the  above  are  fully  described  in  Chapter  VII.  so  no  more 
need  be  said  about  them  here. 

iStapledon,  R.  G.  (1910),  "On  the  Flora  of  Certain  Cotswold  Pastures," 
Scient.  Bull.  Roy.  Agri.  Coll.,  Cirencester,  No.  2;  pp.  29-46. 


GRASS-LAND  WEEDS  179 

($)    Coarse  Growing  Plants  that   Deteriorate   the    Quality  of 
the  Pasture  or  Meadow. 

Cat's  ear  (Hypochceris  radicata). 

Chervil  (Anthriscus  sylvestris). 

Dog  daisy  (Chrysanthemum  leucanthemum). 

Docks  (Rumex  obtusifolius,  etc.). 

Hogweed  (Heracleum  sphondylium). 

Nettles  (Urtica  dioica  and  U.  urens}. 

Rest-harrow  (Ononis  repens). 

Scabious  (Scabiosa  arvensis}. 

Thistles  (Cirsiitm  arvense,  C.  lanceolatum,  Cardnns  nutans). 

Wild  carrot  (Daucus  carota). 

Woodwax  (Genista  tinctoria}. 

Yarrow  (Achillea  millefolium). 

A  few  weeds  in  this  class,  notably  thistles,  nettles,  and 
hogweed,  have  a  certain  nutritive  value  and  are  turned  to 
account  when  cut  down,  and  some  classes  of  stock  will  eat 
them  when  dried. 

(c)  Grasses  and  Plants  of  Low  Feeding   Value. 

False  brorrie  (Brachypodium  sylvaticum  and  B.  pinnatum). 

Soft  brome  (Bromus  mollis). 

Quaker  grass  (Briza  media). 

Rush  (Juncus  spp.}. 

Sedge  (Carex  spp.}. 

Quaker  grass  is  usually  a  sign  of  very  poor  land  and  can 
be  eradicated  by  manurial  improvement  (Fig.  40).  The  other 
two  grasses,  when  circumstances  are  favourable,  tend  to  over- 
run the  pastures  to  the  exclusion  of  species  of  greater  feeding 
value. 

(d)  Parasitic   Weeds. 

Dodder  (Cuscuta   spp.}. 

Eyebright  (Euphrasia  otficinalis). 

Lousewort  (Pedicularis  palustris). 

Yellow  rattle  (Rhinanthus  crista-galli). 

See  Chapter  VI. 

B.  PLANTS  THAT  ARE  CONSIDERED  TO  POSSESS  A  CERTAIN 
FEEDING  VALUE  BUT  ARE  REGARDED  AS  WEEDS  IF 
THEY  ARE  PRESENT  IN  TOO  GREAT  QUANTITY  OR 
GROW  TOO  LUXURIANTLY. 

Bent  grass  (Agrostis  spp.}. 

Couch-grass  (Agropyron  repens}. 

Dandelion  (Taraxacum  vulgar e}. 

Hardhead  (Centaurea  nigra). 

Sheep's  sorrel  (Rumex  acetosella}. 

Silverweed  (Potentilla  anserina). 

Sorrel  (Rumex  acetosa). 

Yorkshire  fog  (Holcus  lanatus). 

12  * 


i8o 


WEEDS  OF  FARM  LAND 


FIG.  40. — QUAKER  GRASS  (Briza  media). 


GRASS-LAND  WEEDS  181 

C.  In  addition  to  the  above  there  are  a  number  of  plants 
that  are  more  or  less  common  denizens  of  grass-land  but  which 
are  difficult  to  classify  definitely  as  weeds.  All  of  them  are 
noxious  if  they  are  present  in  too  great  abundance,  but  this 
is  generally  because  under  such  circumstances  they  crowd  out 
and  usurp  the  place  of  other  plants  of  higher  feeding  value. 
Probably  most  of  the  plants  in  this  category  are  of  some  use 
as  food,  but  little  information  is  available  on. this  point.  In 
this  group  are  included  : — 

Cowslip  (Primula  veris). 

Daisy  (Bellis  perennis). 

Germander  speedwell  (Veronica  chamczdrys). 

Goatsbear  1  (Tragopogon  pratensis). 

Greater  plantain  (Plant ago  major). 

Hoary  plantain  (P.  media). 

Ladies'  bedstraw  (Galium  verum). 

Mouse-ear  chickweed  (Cerastium  vttlgatum). 

Mouse-ear  hawkweed  (Hicracium  pilosella). 
Pignut                                 '  (Conopodium  denudatum). 

Ribwort  plantain  (Plantago  lanceolata). 

Salad  burnet  (Poterium  sanguisorba) . 

Selfheal  (Prunella  vulgaris). 

The  above  lists  must  not  be  taken  as  in  any  way  ex- 
haustive, though  they  include  the  majority  of  the  more  common 
"weeds"  of  grass-land.  Various  other  species  may  occur 
locally,  and  sometimes  a  plant  that  is  uncommon  in  most 
places  may  be  present  in  abundance  in  isolated  fields  in  cer- 
tain districts,  as,  for  example,  fritillary  (Fritillaria  meleagris) 
in  meadows  near  Oxford  and  Framsden  (Suffolk)  and  daffodil 
(Narcissus  pseudo-narcissus}  in  various  parts  of  the  country. 
Bracken  (Pteris  aquilina)  is  often  troublesome  on  common 
grazing  land,  but  is  less  usual  as  a  weed  on  grass-land  that  is 
under  ordinary  farm  management. 

Mosses  and  Fungi. — Two  lower  forms  of  plant  life,  mosses 
and  fungi,  often  give  trouble  in  grass-land  and  must  be  classed 
under  the  heading  of  weeds.  Mosses  are  associated  with  damp 
soil  conditions  and  usually  indicate  poor  drainage.  As  they 
tend  to  spread  thickly  over  the  surface  of  the  soil  they  enter 
into  competition  with  the  herbage  and  prevent  satisfactory 
growth  taking  place,  so  that  the  presence  of  too  much  moss 
indicates  that  the  herbage  is  of  less  value  than  it  might  be. 

Fungi  are  very  commonly  found  on  grass-land  in  damp 
weather,  but  they  give  most  trouble  when  they  form  "  fairy 
rings,"  as  they  cause  the  grass  to  become  very  uneven  in 
growth.  The  rings  are  formed  by  the  action  of  various  fungi 


1 82  WEEDS  OF  FARM  LAND 

which  grow  in  a  particular  way  and  give  rise  to  the  character- 
istic appearance.      The    fungus    consists    essentially    of   long 
white  threads  or  hyphae,  forming  a  mycelium  which  ramifies 
and  spreads  through  the  soil.     At    intervals  this    mycelium 
throws  up  fructifications    popularly  known  as    toadstools    or 
puffballs.      Frequently  these  toadstools  are  fairly  slight  and  of 
a  medium  size,   2-4  inches  across,  but  occasionally  they  are 
very  large  and  solid,  measuring  from  8-IO  inches  in  diameter. 
The  particular  fungi  which  form  the  ring  begin  to  grow 
from  a  central  point  and  branch  outwards  in  all  directions,  the 
fructifications  being  thrown  up  year  after  year  on  the  outer 
edge    of   the   ring,  which  grows  bigger  annually.     The  area 
occupied  by  the  ring  the  previous  year  seems  to  be  particularly 
well    manured    by  the    fungus,  as  the    grass    thereon   grows 
luxuriantly  and  is  always  very  dark  in  colour.      The  affected 
areas   are  marked   out  by  their  luxuriant  growth   and   dark 
colour,  even  in  mowing  fields  in  which  the  grass  is  knee  deep. 
In    pastures  the  grass    of  the  rings  is  much  appreciated  by 
stock  which  keep  it  very  closely  cropped,  but  still  the  dark 
colour  is  evident.     After  one  year  of  heavy  growth  the  transient 
stimulus  is  apparently  exhausted  and  the  herbage  falls  behind 
that  of  the  rest  of  the  field,  indicating  that  the  ground  has 
been  seriously  impoverished.     The  personnel  of  the  herbage 
also  changes.     There  is  no  fixed  scheme  of  colonisation,  but  in 
each  field  the  growth  within  and  without  the  ring  shows  dis- 
tinctive differences.      Sometimes  yarrow  (Achillea  millefolium) 
and   ribgrass   (Plantago  lanceolatd]  appear   among   the  thick 
grass  of  the  ring,   though  they  are  absent  elsewhere  ;  some- 
times cocksfoot  is  the  chief  grass  associated  with  a  good  deal 
of  hogweed.     Another  rather  usual  combination  is  field  brome 
and    rough    meadow-grass,  frequently  combined    with    sorrel 
and  cocksfoot.     One  very  perfect  example  seen  at  Wickwar 
(Glos)  consisted   chiefly  of  ryegrass  and  cocksfoot.      Within 
the  ring  the  herbage  was  shorter  and  showed  a  mixture  of 
grasses  and  weeds  that  indicated  poverty  of  soil.     It  included 
vernal-grass  {Anthoxanthum  odoratum),  rough  meadow-grass, 
dog's  tail,  very  little  cocksfoot  and  an  abundance  of  weeds. 

Too  many  fairy  rings  are  not  desirable  in  grass-land,  but 
unless  they  are  so  abundant  as  to  threaten  the  herbage 
seriously  it  hardly  pays  to  attempt  to  eradicate  them.  Liberal 
manuring  will  do  much  towards  getting  rid  of  them,  but 
definite  efforts  at  eradication  are  better  reserved  for  lawns  and 
special  pieces  of  grass-land. 


GRASS-LAND  WEEDS  *  183 

VEGETATION  OF  SPECIAL  AREAS  OF  GRASS-LAND.1 

In  the  course  of  a  survey  of  grass-land  one  thing  gradually 
forces  itself  upon  the  attention,  i.e.  the  marked  effect  that  slight 
differences  in  level  of  soil  or  conditions  of  life  has  upon  the 
herbage.  Areas  round  gates  and  paths  through  fields  are 
sharply  marked  out  in  this  way,  and  they  are  characterised  by 
a  very  definite  type  of  vegetation. 

Round  the  gates  the  soil  is  usually  much  trodden,  so 
that  its  surface  becomes  more  or  less  free  from  the  ordin- 
ary grasses  of  the  field.  It  often  happens  that  this  trodden 
soil  is  colonised  by  certain  weeds  more  usually  found  on 
arable  land,  such  as  knotgrass  (Polygonum  aviculare),  swine- 
cress  (Senebiera  coronopus),  annual  meadow-grass  (Poa  annua\ 
mayweed  (Matricaria  inodora),  all  plants  that  do  not  intrude 
into  the  general  herbage.  Frequently  the  vegetation  is 
still  more  characteristic.  The  grasses  that  do  occur — often 
rough  meadow-grass  (Poa  trivialis)  (Fig.  41  C) — frequently 
assume  a  prostrate  habit.  One  plant  is  almost  ubiquitous  in 
such  situations.  Wherever  a  field  is  much  trodden,  there  almost 
certainly  to  be  found  is  the  greater  plantain  (Plantago  major] 
(Fig.  41  A),  and  the  more  trodden  the  soil  the  finer  the  plant 
seems  to  grow.  Paths  are  often  demarcated  by  this  plantain, 
and  it  appears  even  in  places  where  not  a  vestige  of  it  occurs 
in  the  regular  herbage.  Silverweed  (Potentilla  anserind]  (Fig. 
41  B)  comes  a  very  good  second  to  the  plantain,  but  is 
more  apt  to  congregate  round  gates  and  cart  tracks  than 
along  footpaths.  Locally  the  broad  dock  (Rumex  obtusifolius) 
and  creeping  thistle  (Cirsium  arvense)  occur  in  abundance,  and 
occasionally  the  hoary  plantain  (Plantago  media)  may  be  ob- 
served. In  one  instance,  at  Falfield,  Glos,  where  the  path 
through  a  field  was  still  green  and  not  bare,  it  was  colonised 
by  a  thick  carpet  of  daisy  (Bellis  perennis)  and  dove's-foot 
crane's-bill  (Geranium  molle) ;  but  this  was  an  exceptional  case. 

Wherever  a  manure  heap  or  stack  is  placed  in  a  field  the 
grasses  underneath  are  more  or  less  completely  killed  out,  and 
on  the  removal  of  the  stack  a  bare  area  is  left  on  which  colonis- 
ation begins.  The  manure  introduces  various  weed  seeds, 
usually  from  arable  fields,  and  such  species  as  knotgrass,  mouse- 
ear  chickweed,  fat  hen,  shepherd's  purse,  chick  weed,  orache, 
thyme-leaved  speedwell,  toadrush  and  groundsel,  may  usually  be 

^renchley,  W.  E.  (1916-17),  "West  Country  Grass-lands,"  Jour.  Bath 
and  West  and  Southern  Counties  Soc.,  XI,  pp.  104-108. 


i84 


WEEDS  OF  FARM  LAND 


FIG.  41. — PLANTS  COMMON  IN  TRODDEN  PLACES. 

A.  Greater  Plantain  (Plantago  major}. 

B.  Silverweed  (Potentilla  anserina). 

C.  Rough-stalked  Meadow-grass  (Poa  trivialis). 


GRASS-LAND  WEEDS  185 

found.  Here  again  the  prostrate  habit  of  the  surviving  grasses 
is  noticeable.  These  may  include  Yorkshire  fog,  cocksfoot, 
and  ryegrass,  as  well  as  rough  meadow-grass,  and  of  these  the 
last-named  is  one  of  the  first  to  resume  the  upright  habit. 
The  effect  of  a  manure  heap  on  the  herbage  that  eventually 
clothes  its  site  is  very  persistent.  After  eighteen  years,  in 
one  case  at  Tortworth  Park,  the  position  was  still  marked  by 
the  super-luxuriant  growth  of  the  grass,  which  lodged  badly 
even  when  the  rest  of  the  field  is  not  at  all  laid. 

On  the  sites  of  old  ricks  arable  weeds  are  not  so  usually 
found,  but  strong  growths  of  broad  dock,  dandelions,  and  nettles 
are  often  seen,  and  these  are  sometimes  surrounded  by  a  ring  of 
cocksfoot  associated  with  sorrel  (Rumex  acetosa).  Field  brome 
(Bromus  arvensis)  is  also  rather  fond  of  such  situations  and 
was  found  dominant  at  Berkeley  on  the  site  of  an  old  heap  of 
grips  (seconds  lime)  that  had  been  spread  on  the  ground. 

In  the  shadow  of  trees  the  herbage  takes  on  a  distinc- 
tive character,  particular  species  growing  in  definite  associa- 
tion. Three  marked  species  are  cocksfoot,  foxtail,  and  rough 
meadow-grass,  but  even  these  are  divided  amongst  themselves. 
In  the  Gloucestershire  fields  cocksfoot  was  to  be  found  in 
abundance  under  almost  every  tree,  sometimes  dominating  the 
situation,  sometimes  with  either  foxtail  or  rough  meadow-grass 
sharing  the  pre-eminence.  The  density  of  shadow  influences 
the  distribution  considerably.  Under  big  trees  which  cast 
very  dense  shade,  cocksfoot  and  foxtail  may  often  be  found 
dominant  towards  the  outer  edge  of  the  shade  ring,  whereas 
in  the  dense  shadow  near  the  bole  they  may  be  replaced  by 
rough  meadow-grass  and  sometimes  by  smooth  meadow-grass 
(Poapratensis).  Less  frequently  under  big  trees  rough  meadow- 
grass  and  foxtail  share  dominance,  with  cocksfoot  only  occur- 
ring occasionally. 

In  some  cases,  where  the  hedges  are  high  enough  to  cast 
a  real  shade,  resembling  the  partial  shade  under  the  smaller 
trees,  cocksfoot  and  foxtail  grow  most  luxuriantly  along  the 
edges  of  the  fields,  forming  bands  many  feet  broad  which  cease 
abruptly  towards  the  edge  of  the  shade  line.  Comparatively 
few  other  species  occur  in  any  quantity  in  the  shadow  of 
trees,  and  usually  only  one  or  two  of  these  are  at  all  conspicu- 
ous in  each  instance.  Tall  and  bulbous  buttercups,  wild 
chervil  (Anthriscus  sylvestris),  sharp  dock  and  broad  dock, 
sorrel,  pignut  (Conopodium  denudatum),  and  field  brome  prac- 
tically sum  up  the  colonists,  though  occasionally  creeping 


1 86  WEEDS  OF  FARM  LAND 

thistle,  nettle,  and  ryegrass  venture  as  far  as  the  outer  edge  of 
the  shade  circle. 

Occasionally  the  vegetation  under  trees  takes  on  a  totally 
different  character.  Under  certain  trees  in  Tortworth  Park 
(Glos)  Bromus  sterilis  absolutely  dominated  the  situation,  in 
some  instances  to  the  total  exclusion  of  all  other  species,  in 
others  admitting  foxtail  on  sufferance.  Under  a  very  large  oak 
tree  on  a  mowing  field,  also  at  Tortworth,  the  deep  shade  was 
colonised  by  an  abundance  of  pignut,  little  else  being  evident 
except  an  undergrowth  of  grass.  Farther  out,  in  the  less 
dense  shadow,  cat's  ear  (Hypochceris  radicata)  was  dominant, 
very  little  pignut  being  present.  At  the  edge  of  the  shade, 
merging  into  the  main  part  of  the  field,  the  cat's  ear  was 
joined  by  masses  of  dog  daisies,  which  also  occurred  in 
abundance  out  in  the  open,  giving  the  field  the  appearance  of 
a  sheet  of  white  and  gold. 

When  fields  are  grazed  by  cattle,  they  are  frequently 
scattered  with  clumps  of  coarse,  luxuriant  grass  that  the 
animals  leave  severely  alone.  These  clumps  spring  up  around 
the  droppings,  and  are  very  generally  composed  largely  or  en- 
tirely of  cocksfoot,  with  or  without  sorrel  in  varying  amount. 
The  cocksfoot  is  obviously  much  encouraged  by  manuring,  and 
under  favourable  circumstances  will  grow  so  strongly  as  to 
overpower  nearly  everything  else.  On  this  account  care  has 
to  be  used  in  the  application  of  dung  to  certain  fields  where 
this  grass  flourishes.  To  some  people  the  prevalence  of  cocks- 
foot in  clumps  round  the  droppings  and  also  under  trees  sug- 
gests that  in  the  latter  case  the  grass  is  encouraged  by  the  fact 
that  the  animals  seek  the  shade  of  trees  during  sunny  weather, 
so  that  the  ground  there  gets  heavily  manured,  thus  giving  the 
cocksfoot  a  grand  opportunity.  This  may  be  true  to  a  large 
extent,  but  even  without  heavy  manuring  cocksfoot  tends  to 
grow  very  luxuriantly  in  the  shade ;  indeed,  in  some  parts  of 
the  world  it  is  called  orchard  grass  because  it  forms  the  chief 
constituent  of  the  herbage  under  the  fruit  trees.  The  tussocks 
disfigure  the  fields  and  help  to  make  the  grass  patchy.  To 
keep  them  down  it  is  well  to  follow  after  cattle  with  horses  or 
sheep,  as  these  have  not  the  same  objection  to  eating  the 
grasses  in  the  clumps. 


CHAPTER    XII. 

USES  OF  WEEDS. 

THE  descriptions  of  plants  given  by  very  early  writers  and 
the  old  herbalists,  as  Dioscorides,1  Pliny,2  Gerarde 3  and 
Parkinson,4  lay  special  stress  upon  their  medicinal  values, 
many  of  which,  to  our  modern  idea,  are  extremely  fanciful 
and  far-fetched.  The  majority  of  wild  plants  then  known 
were  used  for  medical  purposes  or  for  herb  teas,  but  few 
of  these  have  retained  their  reputation  to  the  present  day. 
The  stitchwort  gained  its  name  because  it  was  reckoned 
"  good  against  stitches  and  pains  in  the  side  ".l  The  creeping 
buttercup  was  used  to  raise  blisters  on  the  wrists  of  those 
attacked  by  ague,  and  the  seeds  of  corn  cockle  were  dried, 
powdered  and  used  as  a  cure  for  jaundice.5  Kidney  vetch 
(AntkyUis  vulnerarid)  once  had  the  reputation  of  being  a  good 
cure  for  wounds,  and  hence  received  its  specific  namevulner- 
aria?  while  the  scarlet  pimpernel,  pounded  to  dust  and  drunk 
in  water,  was  regarded  as  a  remedy  for  the  bite  of  a  mad  dog.1 
Many  other  such  ideas  were  rife,  but  all  have  passed  away. 
The  mayweed  was  formerly  much  used  for  medical  purposes, 
but,  curiously  enough,  after  being  practically  neglected  for 
a  long  time  it  came  back  into  use  in  connection  with 
homoeopathy.6  The  juice  of  the  sun  spurge  (Euphorbia  helio- 
scopia)  is  still  sometimes  used  for  removing  warts,7  and  when 
rubbed  on  the  skin  behind  the  ear  is  said  to  be  a  cure  for 
toothache.8 

The  few  weeds  which  are  still  commonly  utilised  in  medi- 
cine, as  colchicum,  hemlock,  and  poppy  are  treated  in  detail 

1  "  Leechdoms,   Wortcunning,  and    Starcraft  of  Early  England "   (1864). 
Collected  and  edited  by  Oswald  Cockayne.     (Includes  Dioscorides,  A.D.  100.) 

2  Pliny's  "  Natural  Historic,"  Holland's  Translation  (1634). 

3  Gerarde,  "  The  Herbal  "  (edited  by  T.  Johnson),  (1633). 

4  Parkinson,  J.  (1629),  "  Paradisi  in  Sole". 

5  Hogg,  R.,  and  Johnson,  G.  W.  (1863),  «*  Wild  Flowers  of  Great  Britain  ". 

6  Wilson  (1847),  "  Rural  Cyclopedia  "< 

7  Knapp,  F.  H.  (1846),  "  Botanical  Chart  of  British  Flowering  Plants  ". 

8  Pratt,  A.,  "  Flowering  Plants,  Grasses,  and  Ferns  of  Great  Britain," 

187 


1 88  WEEDS  OF  FARM  LAND 

later  on  in  the  chapter.  Before  the  increase  in  the  importation 
of  cheap  vegetable  dyes  from  foreign  countries,  and  before  the 
great  advances  made  in  connection  with  chemical  dyes, 
wild  plants  played  an  important  part  in  the  provision  of  these 
essential  articles  of  commerce.  Among  the  weeds,  ladies' 
bedstraw  (Galium  verum),  sorrel  (Rumex  acetosa],  agrimony 
(Agrimonia  eupatorid},  nettle  (Urtica  dioica),  woodwax  (Genista 
tinctoria),  willowweed  (Polygonum  persecaria)  were  all  used  for 
dyes,  and  wild  mignonette  or  dyer's  rocket  (Reseda  luteold), 
besides  providing  a  beautiful  yellow  dye,  was  used  for  making 
the  paint  called  "  Dutch  pink".1  In  the  time  of  Pliny  wild 
orache  was  even  used  to  colour  the  hair  black.2 

Some  of  the  uses  to  which  the  weeds  are  put  are  very 
singular  and  interesting.  The  stalks  of  white  deadnettle 
are  made  into  whistles  by  country  boys,  and  in  the  time  of 
James  I  ladies  used  carrot  leaves  instead  of  feathers.  The 
seed  of  wild  oat  is  provided  with  twisted  awns  which  uncoil 
when  in  contact  with  water,  so  it  has  been  used  as  a  hygro- 
meter, and  also,  as  the  hairs  and  bent-  awn  cause  the  seed  to 
resemble  closely  a  fly,  it  is  used  by  rustic  fishermen  for  catch- 
ing trout.1 

Many  of  the  commonest  farm  weeds  have  a  varied  history 
of  usefulness  in  old  and  modern  times,  and  therefore  they  are 
treated  individually  in  the  following  paragraphs. 

Achillea  millefolium  (Yarrow). — This  plant  is  highly 
astringent  and  was  anciently  much  prized  as  a  vulnerary. 
According  to  the  old  leechdoms  it  was  widely  used  for  curing 
wounds,  and  the  story  runs  that  it  received  its  name  because 
Achilles  found  it  and  used  it  to  cure  those  who  had  been 
wounded  with  iron.3  As  late  as  1863  it  was  used  among  the 
Scottish  Highlanders  to  make  an  ointment  for  drying  and  heal- 
ing wounds,  and  it  is  possible  that  this  is  still  done.4  It  is  a 
useful  astringent  in  cases  of  haemorrhage,  and  yet,  curiously 
enough,  it  is  called  "  nosebleed "  because  the  leaves  are 
supposed  to  cause  bleeding  if  put  into  the  nose.3  In  some 
parts  of  Sweden  and  Africa,  yarrow  has  been  employed  in 
the  making  of  beer  in  order  to  render  it  more  intoxicating.5 
Some  agriculturists  regard  it  simply  as  an  agreeable  condiment 
for  cattle,  while  others  consider  it  to  be  a  most  valuable 
ingredient  in  good  nutritious  herbage. 

1  Lindley,  J.,  and  Moore,  T.  (1889),  "  Treasury  of  Botany". 

2  Pliny,  loc.  cit.  3  Leechdoms,  loc.  cit.     (Includes  Ampuleius.) 

4  Hogg,  R.,  and  Johnson,  G.  W.,  loc.  cit. 

5  Woodville,  W.  (1790-1792),  "  Medical  Botany  ". 


USES  OF  WEEDS  189 

Agrimonia  eupatoria  (Agrimony).  This  has  always  had  a 
considerable  reputation  for  medicinal  purposes,  and  an  infusion 
of  agrimony  was  employed  by  the  peasantry  of  the  south  of 
England  for  feverish  colds.1  The  Canadians  are  also  said  to 
have  successfully  used  an  infusion  of  the  root  in  certain  fevers. 
During  the  war  the  fruits  were  used  as  a  constituent  of  the 
tea  mixtures  sold  in  Germany.  The  plant  contains  tannin 
and  has  been  used  in  Germany  for  dressing  leather.  It  also 
yields  a  good  colouring  matter  which  dyes  wool  bright  nan- 
keen if  the  plant  is  gathered  when  the  flowers  are  beginning 
to  open,  but  if  gathered  in  September  the  dye  is  darker.2 

Agropyron  repens  (Couch-grass). — Although  this  is  such  a 
pestilent  weed,  it  has  great  capabilities  of  usefulness  if  rightly 
employed.  From  very  early  times  its  medical  value  was  recog- 
nised. Pliny  claimed  that  it  was  useful  for  healing  wounds, 
and  that  poultices  made  from  it  prevented  inflammation  of 
injuries.  Gerarde  also  emphasised  the  healing  powers  of  the 
plant,  and  Culpepper 3  went  so  far  as  to  say  that  "  a  physician 
holds  half  an  acre  of  them  to  be  worth  5  acres  of  carrots 
twice  told  over".  Horses  and  cattle  are  particularly  fond  of 
the  rhizomes  or  underground  stems.  At  Chedzoy,  in  Somerset, 
in  1916,  the  couch  grass  that  was  cultivated  out  was  thrown 
into  a  stack,  with  the  intention  of  using  it  for  rick  bottoms. 
Cattle  were  turned  into  the  field,  and  they  made  a  raid  on  the 
stack  and  rapidly  demolished  it,  though  the  stuff  was  never 
fed  to  them.4  In  Rome  and  Naples  the  rhizomes  are  washed 
and  mixed  with  carrots  as  food  for  horses.1  They  contain  a 
considerable  amount  of  nutritive  matter,  similar  in  quality 
and  quantity  to  that  in  the '  potato,  and  this  can  easily 
be  extracted  in  the  form  of  a  starchy  powder  resembling 
arrowroot,  which  is  quite  good  for  human  food.  During  the 
war  a  coffee  substitute  was  prepared  from  the  rhizomes,  and 
the  latter  were  also  dried  and  ground  into  flour. 

Apart  from  its  feeding  value,  couch-grass  is  valuable  as  a 
manure  if  made  into  a  compost  with  lime,  or  burned,  and 
the  ashes  spread  over  the  ground.  The  rhizomes  can  also  be 
worked  up  into  paper,  and  although  the  quality  is  at  present 
not  very  good  it  is  useful  for  rough  work,  and  improvement 
may  be  effected  as  experience  is  gained. 

1  Wilson,  loc.  cit.  2  Hogg  and  Johnson,  loc.  cit. 

3  Culpepper,  "  British  Herbal  ". 

4  Brenchley,  W.  E.  (1917),  "  West  Country  Grasslands,"  your.  Bath  and 
West  and  Southern  Counties  Society,  XI,  pp.  102-103. 


IQO  WEEDS  OF  FARM  LAND 

Agrostis  spp.  (Bent  grass). — This  weed  is  little  used  except 
as  feed  for  animals,  but  in  Italy  and  the  South  of  France  the 
stolons  have  sometimes  been  gathered  into  bundles  by  the  poor 
and  sold  in  the  market  as  horse  provender.1  Agrostis  alba 
has  been  cultivated  for  fodder,  but  this  is  seldom  done  now.2 

A  Ilium  ursinum  (Ramsons). — Gerarde  says  that  in  the 
Low  Countries  the  leaves  were  stamped  and  eaten  as  a  sauce, 
and  that  the  leaves  were  sometimes  eaten  in  April  and  May 
with  butter.3  In  Khamchatka  large  quantities  are  stored  for 
winter  use,  both  for  culinary  purposes  and  as  an  antiscorbutic.4 

Borago  officinalis  (Borage). — The  young  and  tender  leaves 
are  good  in  salads  or  as  a  pot-herb,  and  formerly  were  often 
put  into  negus  or  cold  tankards.  Occasionally  the  leaves  and 
flowers  have  been  employed  as  an  ingredient  in  brewing.1 

Camelina  sativa  (Gold  of  pleasure). — Although  regarded 
as  a  weed  in  England,  this  is  such  a  useful  plant  that  it  is 
cultivated  on  the  Continent  in  Holland,  Belgium,  Germany, 
North  France,  etc.,  and  in  South  Europe  produces  two  crops 
a  year.  It  yields  an  excellent  oil  which  has  practically  no 
smell  and  gives  a  brighter  flame  and  less  smoke  than  oil  of 
rape  or  mustard.1  The  oil  was  noted  even  in  Gerarde's  time, 
for  he  says  it  was  used  by  the  poor  peasants  in  their  banquets, 
and  by  rich  people  in  their  lamps.3  It  is  now  chiefly  used  by 
soapmakers,  The  cake  obtained  after  expressing  the  oil  has 
been  suggested  for  use  as  cattle-food,  but  seems  to  be  too  acrid 
to  be  satisfactory  for  that  purpose.2  The  stems  are  very  fibrous, 
being  tough,  hard,  and  durable,  so  that  they  are  employed  for 
such  purposes  as  thatching  temporary  buildings  and  for  making 
brooms,  sack-cloth,  sailcloth  and  packing  paper.  The  plant 
has  been  used  as  green  fodder  for  sheep,  and  poultry  and 
geese  are  very  fond  of  the  seeds  and  quickly  fatten  on  them.5 

Carex  (Sedge). — The  stiff  strong  leaves  are  occasionally 
used  by  the  poorer  farmers  for  fodder,  litter,  thatch,  and  fuel, 
and  in  Kent  the  leaves  of  the  larger  kinds  have  been  employed 
to  fasten  the  hop-vines  to  the  poles.  The  Laplanders  protect 
their  hands  and  feet  in  winter  with  a  flaxy  fibre  made  from 
sedge,  and  by  the  Italians  it  is  used  to  stuff  crevices  of  casks, 
and  to  make  bottoms  of  chairs  and  covers  for  flasks  of 
Florence  oil.1 

Chenopodium  album  (Fat  hen). — The  seeds  have  occasionally 

1  Wilson,  loc.  cit.  2  Lindley  and  Moore,  loc.  cit. 

3  Gerarde,  loc.  cit.  4  Hogg  and  Johnson,  loc.  cit. 

6  Johnson,  C.  P.  (1861-62),  "  Useful  Plants  of  Great  Britain  ". 


USES  OF  WEEDS  191 

been  ground  into  flour  for  bread-making,  as,  for  instance,  during 
the  Russian  famine  of  I89I-I892.1  They  are  also  used  in  the 
preparation  of  shagreen,  being  pressed  into  the  moist  hides  to 
form  the  granulations  so  characteristic  of  that  leather.2  The 
plants  possess  a  certain  manurial  value  if  they  are  ploughed 
in  when  green,  as  the  potash  content  is  about  10-9  per  cent,  the 
same  as  in  Stellaria  media? 

Cichorium  intybus  (Chicory). — In  France,  Italy,  Switzerland 
and  other  parts  of  Europe  this  has  been  specially  cultivated 
for  stock  feed,  and  was  much  esteemed  for  cows,  being  usually 
made  into  hay.4  In  the  eighteenth  century  the  roots  were 
gathered  for  eating  before  the  flowering  stems  shot  up,  some- 
times being  dried  and  made  into  bread.5  The  more  modern 
use  is  as  a  substitute  or  adulterant  for  coffee.  The  roots  are 
kiln-dried  or  roasted  and  ground  into  powder,  and  added  to 
coffee  either  openly  or  fraudulently  (as  some  people  prefer 
ground  chicory  to  genuine  coffee,  and  others  have  a  strong 
objection  to  it).6  During  the  war  the  value  of  chicory  as  a 
coffee  substitute  was  so  well  recognised  that  in  Germany  and 
Austria  the  whole  crop  was  reserved  for  this  purpose,  its  use 
in  feeding  animals  being  prohibited.  The  dried  roots  contain 
a  good  deal  of  sugar,  and  have  been  used  instead  of  oats  for 
feeding  purposes.7 

In  Belgium  it  has  long  been  used  in  a  pure  state  instead 
of  coffee,  and  in  the  same  country  the  roots,  are  boiled  and 
eaten  like  parsnips.  The  plant  is  much  cultivated  in  some 
parts  of  England,  the  herbage  being  used  as  food  for  cattle 
and  the  roots  as  an  article  of  commerce.  The  leaves  are  often 
blanched  and  eaten  for  salad,8  and  the  roots  possess  medicinal 
properties  closely  resembling  those  of  dandelion.  Altogether 
the  plant  is  distinctly  useful  in  many  ways,  and  it  is  even  stated 
that  this  and  some  very  similar  plants  constitute  half  the  food 
of  the  Egyptians.9  At  the  present  time  it  is  a  most  valuable 
constituent  of  "Elliott's  mixture,"  which  has  proved  so  effica- 
cious in  eradicating  wild  onion  from  arable  land.10 

1  Hanasek,  T.   F.    (1915),   Zeitsch.  fur    Untersuchung  der  Nahrungs-  und 
Genussmittel,  29,  pp.  17-25. 

2  Knapp,  loc.  cit. 

3  Kling,    M.    (1915  ?)    "  tiber    die    chemische    Zusammensetzung    einiger 
Unkrauter  sowie  deren  Wert  als  Futter-und  Diingemittel,"  Landw.  Versuchs- 
Stat,  LXXXV,  pp.  433-470,  Summ.  in  your.  Bd.  Agric.,  XXII,  pp.  362-363. 

4  Andrews,  G.  H.  (1853),  "  Modern  Husbandry,"  p.  287. 

5  Woodville,  W.,  loc.  cit.  6  Wilson,  loc.  cit. 
1  See  your.  Bd.  Agric.,  Vol.  XXIII,  pp.  499-500. 

8  Hogg  and  Johnson,  loc.  cit.  9  Pratt,  loc.  cit. 

10Voelcker,  J.  A.  (1911),  "Eradication  of  Wild  Onion,"  your.  Roy.  Ag. 
Soc.,  72,  pp.  404-409. 


192  WEEDS  OF  FARM  LAND 

Colchicum  autmnnale  (Meadow  saffron). — Like  many  other 
poisonous  plants  the  meadow  saffron  has  valuable  medicinal 
properties,  and  the  seeds  have  often  been  prescribed  for  gout 
and  rheumatism.1  The  Turks  infuse  the  flowers  in  wine  to 
render  it  more  intoxicating,  and  the  bulbs  are  said  to  be  eaten 
with  impunity  in  the  autumn  by  the  peasantry  in  Carniola.2 
The  poisonous  nature  of  all  parts  of  the  plant  causes  it  to 
be  looked  on  askance  in  this  country,  many  instances  of 
poisoning  of  animals  and  human  beings  having  been  traced 
to  this  source. 

Content  maculatum  (Hemlock). — -As  far  back  as  the  time 
of  Theophrastus  a  most  powerful  poisonous  juice,  used  in 
medicine  and  also  for  causing  death,3  was  obtained  from  the 
root  of  this  plant,  and  there  is  a  tradition  that  the  poison 
drunk  by  Socrates  was  hemlock.  The  fruits  are  the  most 
convenient  sources  of  the  alkaloid  coniine  as  used  for  medical 
purposes.  It  is  said  that  the  green  unripe  fruits  possess  the 
major  part  of  the  peculiar  properties  of  the  plant,  and  that 
they  may  be  dried  without  loss  of  activity.1  Hemlock  has  a 
peculiar  sedative  effect  upon  the  motor  nerves  and  occasionally 
used  to  be  prescribed  for  that  purpose,  but  Cushny  states  that 
this  drug,  long  widely  used  in  therapeutics,  has  on  more 
accurate  investigation  failed  to  maintain  its  position  and 
passed  into  disuse.4  The  plant  is  supposed  to  give  off  a 
narcotic  effluvium  which  is  most  active  in  hot  and  dry  seasons 
and  in  warm  countries.  Linnaeus  says  that  sheep  eat  the 
leaves,  but  that  horses,  cows,  and  goats  refuse  them,  while  Ray 
states  that  the  thrush  will  feed  upon  the  fruits  even  when  corn 
is  to  be  had. 

The  plant  is  often  called  kecks  or  caxes,  apparently  be- 
cause spinsters  used  the  stems  for  caxes  to  wind  yarn  upon.2 

Conopodium  denudatum  (Pignut). — The  edible  quality  of 
the  tuberous  roots  has  long  been  recognised,  for,  according  to 
Gerarde,  in  the  seventeenth  century  the  Dutch  people  ate  them 
boiled  and  buttered,  as  we  do  parsnips  and  carrots.5  They 
have  a  flavour  scarcely  inferior  to  that  of  chestnuts,  and  it  is 
possible  that  in  Holland  and  the  Alps  they  are  still  so  used. 
Apparently  they  are  palatable  and  very  nutritious,  either  raw, 

1  Fliickiger    and    Hanbury    (1874),    "  Pharrnacographia  :    A    History    of 
Drugs". 

2  Hogg  and  Johnson,  loc.  cit. 

3  Theophrastus,  322  B.C.,  «'  Enquiry  into  Plants,"  (Hort's  Translation). 

4  Cushny,  A.  R.  (1918),  "  Pharmacology  and  Therapeutics,  or  the  Action  of 
Drugs,"  p.  306. 

5  Gerarde,  loc.  cit. 


USES  OF  WEEDS  193 

roasted,  or  boiled,  and  Wilson  thought  it  a  great  pity  that 
earthnuts  were  not  cultivated  as  an  article  of  dessert1  In 
some  parts  of  England  they  are  sliced  and  put  into  soups,  and 
in  Sweden  they  are  extensively  used  and  form  a  regular  market 
article.  Pigs,  with  their  keen  sense  of  smell,  are  able  to  de- 
tect the  pignuts2  underground  as  they  do  truffles.  During 
the  war  the  use  of  this  plant  was  advocated  as  a  vegetable.3 

Convolvulus  arvensis  (Bindweed). —  Is  greatly  enjoyed  by 
rabbits  in  captivity.  Analytical  and  feeding  experiments  in 
Germany  (1914)  have  shown  that  the  green  stems  and  leaves 
have  a  high  nutritive  value  as  green  fodder,  and  that  they  are 
also  useful  in  manure.4 

Equisetum  arvense  (Horsetail). — Is  disliked  in  pastures,  for 
although  it  is  eaten  by  horses  it  is  injurious  to  sheep,  and 
causes  violent  scouring  in  cattle  when  forced  to  eat  it  by 
hunger.1  It  has  a  considerable  economic  value  as  it  abounds 
in  particles  of  mineral  matter,  rendering  this  and  other  species 
particularly  suitable  for  polishing  hardwoods,  ivory,  brass,  etc. 
An  allied  species,  E.  hyemale,  used  to  be  imported  from 
Holland  under  the  name  of  "  Dutch  rushes  "  and  was  used  by 
Northumberland  dairymaids  for  cleaning  milk  pails.5 

Fumaria  officinalis  (Fumitory). — Is  readily  eaten  by  cows 
and  sheep,  but  horses  will  not  touch  it  and  goats  dislike  it 
when  it  is  full  grown.1  The  whole  plant  has  a  considerable 
medicinal  reputation  as  a  blood  purifier  and  cosmetic,  the 
leaves  being  the  most  effective  part.  The  Japanese  recognise 
the  medicinal  value  of  the  plant.  In  Picardy  the  plant  is 
used  to  curdle  milk.2 

Galium  aparine  (Goosegrass). — In  the  time  of  Dioscorides 
goosegrass  was  made  into  filters  for  straining  milk,  and, 
Linnaeus  mentioned  that  in  his  day  the  stalks  were  applied  to 
the  same  purpose.  Even  in  our  country  places  it  is  occasion- 
ally used  in  this  way  when  a  sieve  is  not  at  hand.6  In  Sweden 
the  horny  fruits  are  dried  and  slightly  roasted  as  a  substitute 
for  coffee,7  and  they  have  also  been  thoroughly  ground  for 
cattle  food.8  Occasionally,  too,  the  dried  plant  is  infused  in 


1  Wilson,  loc.  cit.  2  Hogg  and  Johnson,  loc.  cit. 

3Crichton  Browne,  J.  (1917),  "A  Neglected  Source  of  Food  Supply," 
Selborne  Magazine,  Vol.  XXVIII,  pp.  85-87. 

4  Kling,  loc.  cit.  5  Knapp,  loc.  cit. 

6  Pratt,  loc.  cit.  7  Johnson,  C.  P.,  loc.  cit. 

8  Bernatsky,  J.  (1915).  See  "  Internal.  Review  Science  and  Practice  of 
Agriculture"  (1916),  VII,  pp.  245-246. 

13 


1 94  WEEDS  OF  FARM  LAND 

hot  water  and  drunk  as  tea.  A  red  dye  can  be  obtained 
from  the  root. 

Galium  verum  (Ladies'  bedstraw). — The  plant  is  of  distinct 
value  in  dyeing,  as  a  bright  yellow  colour  is  obtained  from  the 
flowering  tops  boiled  in  alum,  and  the  roots  yield  a  red  dye 
equal  to  madder.1  The  plant  is  made  use  of  by  the  High- 
landers, who  boil  the  roots  with  the  yarn,  adding  alum  to  fix 
the  colour.2  Some  authorities  say  the  dye  is  superior  to 
madder,  and  at  one  time  it  was  recommended  for  cultivation, 
when  experimental  plots  yielded  a  crop  of  \2\  cwt.  dried  roots 
per  acre.  It  has  been  supposed  that  the  bones  of  animals 
turned  red  if  the  beasts  fed  on  this  plant,  the  colouring 
taking  place  sooner  in  young  than  in  fully  grown  animals, 
while  it  was  deepest  in  those  whose  bones  were  hardest  and 
thickest.3  The  popular  name  of  "cheese  rennet"  is  derived 
from  the  fact  that  the  whole  plant  when  bruised  will  curdle 
milk,  and  in  the  Hebrides  it  is  used  for  this  purpose,  combined 
with  leaves  of  common  nettle  (Urtica  dioicd]  and  a  little  salt. 
It  is  also  used  both  to  colour  and  flavour  milk  intended  for 
cheese,  and  vinegar  is  sometimes  made  from  its  juices. 

Genista  tinctoria  (Wood-wax). — This  yields  a  bright  yellow 
dye,  and  if  articles  dyed  with  it  are  then  dipped  into  a  blue 
solution  of  woad  (I satis  tinctoria]  the  celebrated  "  Kendal 
green  "  is  obtained.4  The  colour  is  fixed  with  alum,  cream 
of  tartar,  and  sulphate  of  lime.5 

Geum  urbanum  (Avens). — The  herbage  is  greedily  devoured 
by  sheep,  and  when  young  may  be  used  for  salads  and  other 
culinary  purposes.1  The  plant  was  much  esteemed  by  her- 
balists, and  since  1780  has  been  used  as  a  febrifuge,6  and  has 
even  been  recommended  as  a  substitute  for  Peruvian  bark  in 
the  cure  of  intermittent  fevers.  If  gathered  in  spring  and  put 
into  ale  avens  gives  the  liquor  a  pleasant  flavour  and  prevents 
it  turning  sour.  The  root,  if  chewed,  is  said  to  overcome 
disagreeable  odour  of  the  breath.  Medically  it  was  once  much 
in  repute  as  a  specific  for  diarrhcea  and  dysentery.7 

Heracleum  sphondylium  (Hogweed). —  Has  been  extensively 
used  in  Sussex  for  fattening  hogs,  and  makes  good  nourishing 
food  for  cattle.1  In  the  Hebrides  the  stems  are  eaten,  and 
an  attempt  has  been  made  to  manufacture  sugar  from  the 

1  Wilson,  loc.  cit,  2Knapp,  loc.  cit. 

3  Pratt,  loc.  cit.  4Lindley  and  Moore,  loc.  cit. 

5  Johnson,  loc.  cit.  6  Woodville,  loc.  cit. 

7  Stephenson,  J.,  and  Churchill,  J.  M.  (1834),  "  Medical  Botany  ". 


USES  OF  WEEDS  195 

stalks,  but  as  it  requires  40  Ibs.  of  dried  stalks  to  produce  one 
Ib.  of  sugar,  the  amount  of  labour  required  renders  the  process 
too  expensive.1  The  inhabitants  of  Kamtchatka  make  a 
great  delicacy  from  this  plant  by  peeling  the  stalks,  drying 
them  in  the  sun,  and  then  laying  them  in  the  shade  in  bags 
till  a  saccharine  efflorescence  is  formed.  This  is  shaken  off 
and  eaten  and  has  a  taste  like  liquorice.  The  Russians  pre- 
pare the  stalks  in  the  same  manner  and  then  distil  an  ardent 
spirit  by  fermenting  them  in  water  with  bilberries  (  Vaccinium 
uliginosuni}.  This  spirit  is  said  to  be  superior  to  that  distilled 
from  corn.4 

Linaria  vulgaris  (Toadflax). — In  Sussex  the  plant  used  to 
be  called  gallwort  and  was  put  into  the  water  drunk  by  poultry 
in  order  to  cure  them  when  drooping.  The  flowers  afford  a 
yellow  dye,  and  in  Sweden  the  plant  is  boiled  in  milk  and  used 
to  attract  and  destroy  flies.1  It  has  some  medical  value  as  a 
purgative.4 

Lithospermum  arvense  (Corn  gromwell). — The  outer  part 
of  the  root  is  red  and  stains  paper,  linen,  oily  substances,  and 
the  human  skin.3  A  rustic  substitute  for  rouge  is  obtained 
from  the  roots,1  which  is  used  to  give  a  brighter  tint  to  their 
cheeks  on  festive  days  by  the  girls  in  the  north  of  Sweden. 
It  also  provides  a  colouring  matter  for  ointments,  hence  obtain- 
ing the  name  "  bastard-alkanet ". 

Nepeta  glechoma  (Ground-ivy).  — According  to  Wilson 
ground-ivy  or  ale  hoof  was  a  chief  ingredient  in  the  manufacture 
of  ale  by  the  ancient  Saxons,  and  in  his  time  was  still  occasion- 
ally used  by  the  poor  for  infusion  in  ale  or  beer,  as  a  remedy 
against  internal  disorders.3  Other  authorities  state  that  it  was 
formerly  used  in  the  fermentation  of  beer  and  other  liquors, 
to  cause  the  foam  on  the  fermented  drink.  If  the  leaves  are 
thrown  into  the  vat  with  ale  they  clarify  it  and  give  it  a  special 
flavour.  Ale-hoof  was  generally  used  for  this  purpose  till  the 
reign  of  Henry  VIII,  when  hops  were  substituted  and  soon 
ousted  the  older  plant  from  favour.4  As  late  as  1889,  and 
possibly  to  the  present  day,  ground-ivy  was  held  in  repute  by 
village  herbalists,  who  dried  it  and  used  it  as  a  substitute 
for  tea.2  For  obstinate  coughs  it  is  a  favourite  remedy  with 
the  poor,  but  is  not  much  valued  by  the  medical  profession.5 

Orchis  mascula  (Early  orchis). — The  roots  of  this  orchis 
and  some  allied  species  are  extensively  used  for  the  manu- 

1  Pratt,  loc.  cit.  2  Lindley  and  Moore,  loc.  cit.  3  Wilson,  loc.  cit. 

4  Hogg  and  Johnson,  loc.  cit.  5  Woodville,  loc.  cit. 

13* 


196  WEEDS  OF  FARM  LAND 

facture  of  the  food-stuff  called  "  salep  "  or  "  saleep  ".  Orchis 
mascula  is  very  plentiful  in  the  moist  meadows  of  Gloucester- 
shire and  other  parts  of  England,  and  is  much  cultivated  in 
the  East,  where  it  yields  a  considerable  portion  of  the  diet  of 
the  inhabitants  of  Turkey,  Persia  and  Syria.  The  root  is 
heated  and  dried  in  the  air,  and  forms  a  somewhat  horny 
substance  called  salep,  which  is  supposed  to  contain  a  very 
large  quantity  of  nutritious  matter  within  a  very  small  bulk. 
It  has  the  property  of  concealing  the  taste  of  salt  water  and 
of  retarding  the  natural  souring  of  milk,  and  in  certain  pro- 
portions it  is  said  to  be  a  very  useful  and  profitable  addition 
to  bread.1  Opinions  differ  as  to  its  medicinal  value,  some 
authorities  claiming  that  it  is  of  considerable  service  in  several 
diseases,  others  denying  that  it  is  of  much  use  in  this  respect. 

Ornithogalum  pyrenaicum  (Spiked  Star-of-Bethlehem). — 
This  weed  is  very  local  in  occurrence,  but  round  about  Bath 
it  is  so  abundant  that  the  young  shoots  or  flowering  spikes 
are  collected  in  the  spring  and  sold  in  the  market  as  a  substi- 
tute for  asparagus,  hence  the  variety  of  popular  names  con- 
nected with  "asparagus" — Bath  asparagus,  French  asparagus, 
Prussian  asparagus.'2  It  would  probably  be  improved  by 
cultivation.  .  The  seeds  are  said  to  impart  a  flavour  to  bread.3 

Papaver  rkceas  (Red  poppy). — The  valuable  properties  of 
this  plant  have  long  been  recognised,  as  even  in  the  time  of 
Theophrastus  (circa  322  B.C.)  it  was  used  in  medicine.  Pliny 
acknowledged  the  narcotic  nature  of  the  poppy,  and  stated 
that  it  reduced  inflammation  of  the  eyes  when  used  as  a  liniment. 
At  the  present  time  this  particular  species  is  chiefly  valued  for 
its  petals  which  yield  a  fine  red  colouring  matter,  especially  if 
used  in  the  fresh  state.  The  petals  are  collected  for  making 
a  coloured  syrup  which  has  very  slight  narcotic  properties.2 
Opinions  differ  as  to  whether  the  seeds  are  also  narcotic, 
but  they  contain  a  farinaceous  substance,  combined  with  a 
bland  oil  which  is  expressed  for  use.  This  poppy  oil  is 
particularly  sweet  and  wholesome  and  is  often  mixed  with 
or  used  instead  of  olive  oil  for  domestic  purposes  and  for 
painting.  The  cake  or  residue  after  the  oil  is  expressed  forms 
a  nutritious  food  for  cattle.  In  some  parts  of  Europe  and  the 
East  poppy  seeds  are  baked  in  cake  or  strewn  upon  bread 
and  butter,  and  the  Genoese  encrust  them  with  sugar  and  eat 
them  as  comfits.  They  are  also  eaten  by  Egyptians  and 

1  Wilson,  loc.  cit.  2  Lindley  and  Moore,  loc.  cit. 

8  Hogg  and  Johnson,  loc.  cit. 


USES  OF  WEEDS  197 

Persians  and  were  used  by  ancient  peoples  to  excite  an  appe- 
tite, and  in  Poland  and  Russia  they  form  an  ingredie'nt  in 
soups  and  gruel.  Poppy  seed  is  given  to  singing  birds  as  a 
cooling  food  when  they  are  moulting,  and  is  then  called  "  maw 
seed".1 

Plantago  lanceolata  (Ribwort  plantain). — This  weed  is  said 
to  serve  a  useful  purpose  by  preventing  the  soil  from  being 
washed  away  on  thin  soil  overlying  rocky  substrata,  as  in  the 
Welsh  mountains,  and  it  has  been  known  thus  to  keep  a  large 
area  fertile  which  would  otherwise  have  been  barren.1  It  has 
also  been  sown  on  sandy  land  as  food  for  sheep.2 

Plantago  major  (Greater  plantain). — According  to  Pliny 
this  plantain  is  very  astringent  and  was  used  instead  of  a 
cautery  or  searing  iron,  but  it  is  rather  doubtful  if  he  really 
meant  our  modern  species.  In  the  old  Leechdoms  or  medical 
works  many  medicinal  properties  were  attributed  to  plantain, 
some  of  which  seem  more  fanciful  than  real.  The  leaves  of 
this  species  and  of  Plantago  media  (hoary  plantain)  are  often 
applied  to  wounds  by  poor  people.  The  seeds  are  very  muci- 
laginous and  useful  in  pulmonary  diseases,  and  are  also  much 
in  demand  among  bird  fanciers  as  food  for  canaries.2  The 
mucilage  of  some  species  of  plantain  is  used  by  manufacturers 
for  stiffening  muslins. 

Polygonum  aviculare  (Knotgrass). — The  fruit  is  emetic  and 
purgative,3  and  the  whole  plant  is  greedily  eaten  by  pigs,  so 
that  in  some  countries  it  is  called  hog- weed.  Gerarde  states 
that  it  used  to  be  given  to  pigs  when  they  were  sick  and  would 
not  eat  their  food.  In  Alsace  knotgrass  has  been  largely  used 
for  making  into  hay,1  and  it  is  said  to  be  very  useful  in  rear- 
ing silkworms.4  Thunberg  says  that  in  Japan  a  blue  dye  re- 
sembling indigo  is  prepared  from  this  plant. 

Polygonum  convolvulus  (Black  bindweed). — Some  writers 
claim  that  the  seeds  are  quite  as  good  as  those  of  buckwheat 
and  that  they  are  produced  in  greater  abundance.  The  juice 
expressed  from  the  bruised  leaves  is  very  purgative.1 

Potentilta  anserina  (Silverweed). — The  silvery  foilage  is 
greatly  relished  by  geese.  The  roots  are  eagerly  eaten  by  pigs 
and  much  appreciated  by  children,  who  roast  them  over  the 
fire.  In  the  Hebrides  the  roots  are  an  article  of  diet,  either 
raw  or  boiled.  They  contain  a  good  deal  of  nutriment  and  in 
times  of  scarcity  the  people  of  the  islands  of  Tiree  and  Coll 

1  Hogg  and  Johnson,  loc.  cit.  2Knapp,  loc.  cit. 

3  Lindley  and  Moore,  loc.  cit.  4  Pratt,  loc.  cit. 


198  WEEDS  OF  FARM  LAND 

have    used    them   for  bread    and  lived    for   months  together 
almost  entirely  on  this  food.1 

Potentilla  reptans  (Cinquefoi!). — The  roots  contain  tannin 
and  have  been  employed  in  the  preparation  of  leather.2  A 
quaint  old  use  of  the  plant  is  that  given  by  Pliny — that  "  it 
is  used  for  purging  or  blessing  of  the  house  against  naughtie 
spirits  or  enchantments  ". 

Potentilla  tormentilla  (Tormentil). — The  roots  provide  a 
most  agreeable  astringent,  aromatic  and  efficacious.  In  the 
western  isles  of  Scotland  and  in  the  Orkneys  they  are 
used  for  tanning  leather  and  are  considered  to  be  superior  to 
oak  bark  ;  they  are  boiled  in  water  and  the  leather  is  then 
steeped  in  the  cold  liquid.  The  roots  also  contain  a  red 
colouring  principle,  soluble  in  alcohol  but  insoluble  in  water.3 

Poterium  sanguisorba  (Salad  burnet). — The  herbage  has 
much  the  flavour  of  cucumber  and  was  used  in  the  old  English 
drink  known  as  "cool  tankard".3  The  French  and  Italians4 
esteem  it  as  a  salad. 

Pteris  aquilina  (Bracken). — Wilson  gives  an  excellent 
summary  of  the  various  uses  of  this  plant.  In  earlier  days  it 
was  in  great  request  for  thatch,  it  was  formerly  employed  in  the 
manufacture  of  both  glass  and  soap,  and  possesses  sufficient  as- 
tringency  for  the  purpose  of  the  tanner.  In  seasons  of  scarcity 
it  makes  useful  fodder,  and  it  forms  good  litter  in  the  cow 
house  and  piggery.  Bracken  often  serves  as  tolerably  good 
manure  for  potato  crops,  and  is  used  for  the  winter  protection 
of  esculent  roots.  It  is  a  common  fuel  for  heating  ovens  and 
burning  lime — and  yet,  is  one  of  the  greatest  pests  of  pastoral 
farms  and  renders  an  enormous  aggregate  of  our  country  un- 
available for  agricultural  purposes.4  In  Scotland  it  is  employed 
as  a  vermifuge.5  It  is  reported  that  the  young  fronds  make  a 
good  fodder  for  pigs  if  they  are  mixed  with  potatoes,  steamed 
and  pounded,  and  also  that  the  rhizomes  are  rich  in  food 
material,  especially  before  the  end  of  April,  and  may  be  fed  to 
pigs.6  Experiments  made  during  the  war  show  that  a  good 

1  Pratt,  loc.  cit.  2  Hogg  and  Johnson,  loc.  cit. 

3  Lindley  and  Moore,  loc.  cit. 

4  Wilson,  loc.  cit.  5  Knapp,  loc.  cit. 
6  (a)  Zeit-Nahrungs  Genussmittel  (1916),  32,  p.  447. 

(b)  "The  Uses  of  Bracken  Fronds  and  Roots,"  Jour.  Bd.  Agric.  (1917), 
XXIII,  1252-1255. 

(c)  Hansen  und  Mez  (1916),  "  On  the  Use  of  Fern-root  (Pteris  aquilina)  in 
German  Pig-feeding  Experiments,"  Deutsche  landwirtsch.  Presse.,  43,  No.  22, 

P-  193. 

(d)  Weiner  Landw.  Ztg.  (April  22,   1916),    Summ.    in   Jour.  Bd.  Agric., 
XXIII,  p.  499. 


USES  OF  WEEDS  199 

deal  of  potash  can  be  obtained  by  burning  bracken  and  utilis- 
ing the  ash.1 

Ranunculus  acris  (Tall  buttercup). — Possesses  a  very  acrid 
juice  and  is  sometimes  used  fresh  as  a  plaster  for  causing  local 
irritation,  as  in  cases  of  rheumatism  and  hip  disease.  Care  is 
needed  in  application,  or  it  may  cause  ulcers,  .but  the  plant 
loses  its  virulence  on  dying.  Withering  says  that  beggars  use 
it  to  ulcerate  their  feet,  which  they  expose  in  that  state  to 
excite  compassion.2  The  curious  superstitions  that  attach 
themselves  to  some  plants  are  well  exemplified  in  this  case, 
for  Ampuleius  wrote,  "  For  a  lunatic,  take  this  wort  and 
wreathe  it  with  a  red  thread  round  a  man's  neck  when  the 
moon  is  on  the  wane,  in  the  month  which  is  called  April,  in 
the  early  part  of  October,  soon  he  will  be  healed  ".3 

Rhinanthus  crista-galli  (Yellow  rattle). — The  plants  are 
supposed  to  be  useful  for  exterminating  vermin,  if  the  seeds 
and  seed  vessels  are  boiled  in  water  and  poured  over  the  haunts 
of  bugs  and  fleas  or  over  animals  infested  with  lice.4 

Rumex  acetosa  (Sorrel). — The  leaves  of  this  plant  are  acid 
and  astringent,  and  were  much  cultivated  in  gardens  for 
eating  cooked  or  as  salads,  especially  in  the  time  of  Henry 
VIII.  It  has,  however,  been  almost  entirely  supplanted  for 
this  purpose  by  the  French  sorrel,  which  has  large  succulent 
leaves,  and  the  native  species  has  almost  disappeared  from 
cultivation.5  A  rustic  custom,  which  probably  still  survives,  is 
to  serve  it  as  sauce  with  roasted  meat,  hence  the  name  "  green 
sauce  ".  The  herb  is  also  beaten  to  a  mash  and  mixed  with 
vinegar  and  sugar.  In  some  parts  of  Ireland  the  plant  is  eaten 
with  milk  and  fish,  and  is  capable  of  souring  milk,  being  so  used 
by  the  Laplanders.4  A  fine  red  dye  is  obtained  by  boiling  the 
dried  root.  In  some  parts  of  Sweden  when  it  is  difficult  to 
cultivate  barley  or  rye,  a  bread  made  from  bark  and  another 
made  from  common  sorrel  often  stand  between  the  poor 
people  and  starvation.6 

•  A  substitute  for  salt  of  lemon  used  to  be  extracted  from 
the  roots  in  Germany  and  exported  to  England.  In  its  pre- 
paration the  mucilaginous  parts  were  separated  by  use  of  water 
and  pipeclay  and  the  salt  was  purified  by  several  crystallisa- 
tions.4 It  was  also  much  employed  in  making  verjuice. 

1  Berry,  R.  A.,  Robinson,  G.  W.,  and  Russell,  E.  J.  (1918),  "  Bracken  as  a 
Source  of  Potash,"  Jour.  Bd.  Agric.,  XXV,  pp.  i-u. 

2  Woodville,  loc.  cit.  -Leechdoms,  etc.,  loc.  cit. 

4  Hogg  and  Johnson,  loc.  cit.  5  Lindley  and  Moore,  loc.  cit. 

6  Pratt,  loc.  cit. 


200  WEEDS  OF  FARM  LAND 

The  weed  is  of  little  agricultural  importance,  as  it  is  never 
eaten  by  live  stock  unless  they  are  unusually  hungry,  but  its 
medicinal  value  as  a  cure  or  preventive  of  scurvy  was  recog- 
nised by  some  of  the  oldest  writers. 

Rumex  obtusifolius  (Broad-leaved  dock). — Cattle  will  not 
eat  the  plant,  but  in  the  North  of  England  the  boiled  foliage 
is  used  as  food  for  pigs.  Withering  states  that  fallow  deer  eat 
it  so  greedily  that  it  is  rare  to  see  a  dock  growing  in  a  deer 
park.  The  name  "  butter-dock "  is  given  because  the  large 
leaves  are  often  employed  for  wrapping  round  butter  and  cheese. 
The  root  is  very  astringent,  and  acts  in  the  same  way  as  the 
powder  or  tincture  of  Turkey  rhubarb.  It  was  formerly  used 
by  dyers,  and  when  powdered  makes  an  excellent  dentifrice.1 

Rushes  are  among  the  plants  that  have  gradually  decreased 
in  importance  with  the  progress  of  civilisation.  Nowadays 
rushes  are  considered  chiefly  as  troublesome  weeds,  which  are 
to  be  eradicated  whenever  possible.  In  older  times  many 
useful  articles  of  household  economy  were  made  from  them 
as  they  were  worked  up  into  mats  and  into  baskets  of  all 
descriptions,  from  coarse  fishing  baskets  to  finely  woven  ware.2 
The  familiar  term  "  rushlights  "  points  to  the  use  of  the  pith 
of  some  rushes  for  making  candles.  Little  baskets  and 
children's  toys  were  made  from  the  same  pith.  When  twisted 
together  rushes  were  used  to  make  ties  for  bundles  and  other 
rustic  implements,  and  it  is  probable  that  they  provided  the 
material  for  the  earliest  cordage.  Indeed,  the  rushes  of  some 
countries  are  commonly  made  into  ropes  and  cables,  and  in 
this  country  mats  and  chair  bottoms  were  formerly  manu- 
factured from  them.1 

Scleranthus  annuus  (Annual  knawel). — Cattle  refuse  to  eat 
this,  but  sheep  and  goats  will  feed  on  it.3  In  some  parts  of  the 
continent,  as  Sweden  and  Germany,  it  is  said  that  a  decoction 
is  made  and  the  steam  inhaled  as  a  remedy  for  toothache.4 

Senecio  vulgaris  (Groundsel). — This  abundant  weed  seems 
to  be  of  little  use  for  any  purpose  except  as  a  food  for  cage 
birds.  Few  animals  care  for  it  except  goats  and  pigs.3  The 
expressed  juice  has  been  used  to  cause  the  evacuation  of  bot 
worms  from  horses.4  The  bruised  leaves  are  healing  if  applied 
to  boils,  and  an  infusion  can  be  used  in  small  doses  as  a  purga- 
tive and  in  large  quantities  as  an  emetic.  It  was  far  more 
valued  by  the  old  herbalists  than  it  is  now. 

1  Pratt,  loc.  cit.  z  Pliny,  loc.  cit. 

8  Wilson,  loc.  cit.  4  Hogg  and  Johnson,  loc.  cit. 


USES  OF  WEEDS  201 

Silene  inflata  (Bladder  campion). — The  boiled  leaves  are 
supposed  to  taste  like  peas  or  asparagus.  They  are  eaten  by 
the  natives  of  Zante,1  and  were  also  used  by  the  inhabitants 
of  Minorca  in  1655  after  the  corn  crop  had  been  destroyed  by 
locusts.2 

Sonchus  oleraceus  (Common  sowthistle). — The  bitter  milky 
roots  have  occasionally  been  used  for  making  bread.3  The 
leaves  were  formerly  eaten  in  Italy  as  salad,  but  have  long 
been  replaced  by  more  palatable  plants.4  Hares  and  rabbits 
are  greedily  fond  of  the  leaves,  goats  like  it,  and  other  animals 
often  feed  upon  the  plant. 

Spergula  arvensis  (Spurry). — Although  spurry  is  regarded 
simply  as  a  pestilent  weed  in  this  country,  it  is  much  valued 
abroad  as  cattle  food.  Beasts,  sheep,  and  poultry  are  very 
fond  of  it,  and  it  has  excellent  fattening  properties.  Old 
writers  state  that  in  the  Low  Countries  two  crops  can  be 
obtained  in  a  year,  the  first  from  a  May  sowing,  when  the 
plants  ripen  seed  in  August,  and  the  second  from  a  sowing 
made  after  rye  harvest,  which  provides  feed  until  the  New 
Year.5  The  crop  is  either  used  as  pasture,  cut  green,  or 
made  into  hay.  It  improves  the  mutton  of  sheep  and  the 
milk  and  butter  of  cows,  and  is  said  to  cause  hens  to  lay  more 
freely.3  The  seeds  can  be  ground  into  a  kind  of  flour,  which 
makes  a  fair  bread,  especially  if  mixed  with  wheat  or  rye  flour. 
It  is  often  used  for  this  purpose  in  Norway  and  Finland, 
particularly  when  other  crops  are  short.6  The  seeds,  when 
bruised,  form  a  good  cattle  food,  and  when  expressed  they  also 
yield  a  good  lamp  oil. 

Stellaria  media  (Chickweed). — Is  of  little  use  except  as 
food  for  birds  and  pigs,  which  are  very  fond  of  it.  It  has 
been  boiled  for  use  as  spinach,  and  is  said  to  have  some 
nutritive  value  when  treated  in  this  way.3  German  experi- 
ments indicate  that  the  weed  has  considerable  manurial  value, 
as  it  contains  about  10*9  per  cent,  of  potash.7 

Taraxacum  vulgar e  (Dandelion). — In  the  time  of  Gerarde 
and  Parkinson  this  was  much  valued  for  medicinal  purposes, 
and  it  is  still  recognised  in  therapeutics,  though  it  does  not 
rank  high  in  value.  The  ground  root  is  sometimes  mixed 
with  chocolate  to  make  a  palatable  kind  of  dandelion  tea.8 

1  Knapp,  loc.  cit.  2  Hogg  and  Johnson,  loc.  cit. 

3  Wilson,  loc.  cit.  *  Lindley  and  Moore,  loc.  cit. 

5Houghton  (1728),  "  Husbandry  and  Trade  Improved,"  II,  p.  374. 
6  Pratt,  loc.  cit.  7  Kling,  loc.  cit. 

8  Johnson,  loc.  cit. 


202  WEEDS  OF  FARM  LAND 

Theophrastus  considered  that  the  plant  was  too  bitter  to  be 
fit  for  human  food,  but  nowadays  the  young  leaves  are  blanched 
and  much  relished  in  spring  salads.  The  French  people  eat 
the  young  roots  as  well  as  the  blanched  leaves  with  bread  and 
butter,1  and  in  parts  of  Germany  the  roots  are  roasted,  ground, 
and  drunk  instead  of  coffee  by  the  poorer  people,  who  claim 
that  the  beverage  so  prepared  can  hardly  be  distinguished 
from  genuine  coffee.2  As  fodder  it  is  much  liked  by  rabbits, 
pigs,  and  goats,  but  sheep  and  cattle  do  not  care  for  it  and 
horses  will  not  touch  it.3  The  leaves  are  sometimes  used  for 
feeding  silkworms  when  mulberry  leaves  are  not  available.4 

Tussilago  farfara  (Coltsfoot). — For  many  centuries  the 
plant  has  been  used  in  chest  and  lung  troubles.  Even  in 
Pliny  we  read:  "If  the  root  of  F'olefoot  be  burnt  upon  the 
coles  made  with  Cypres  wood  the  smoke  ...  is  singular  for 
an  old  cough ".  The  leaves  have  certain  demulcent  and 
pectoral  properties,  and  are  employed  in  the  manufacture  of 
British  herb  tobacco,  of  which  they  form  the  chief  ingredient, 
and  which  was  formerly  much  used  in  chest  complaints.3  The 
smoking  of  the  plant  was  strongly  recommended  by  the  old 
writers.  The  cottony  down  from  the  leaves  has  sometimes 
been  utilised  for  filling  pillows  and  cushions,5  and  it  also 
makes  a  most  excellent  tinder  when  wrapped  in  a  rag,  dipped 
in  a  solution  of  saltpetre,  and  dried  in  the  sun. 

Ulex  europaeus  (Gorse). — Although  this  can  hardly  be 
reckoned  as  an  ordinary  farm  weed,  it  has  so  many  uses  that 
it  may  find  a  place  here.  In  spite  of  its  spiny  habit  it  forms 
a  most  excellent  forage,  though  the  older  branches  need  to 
be  bruised  with  a  mallet  before  being  fed.  Old  writers  say 
that  cattle  appreciate  it  greatly  and  fatten  on  it  as  well  as  they 
do  on  turnips,  that  the  milk  of  cows  is  as  plentiful  as  though 
they  were  fed  on  grass,  and  the  butter  produced  of  excellent 
quality.6  More  recent  work  indicates  that  the  gorse  should  be 
well  crushed  and  freshly  prepared,  in  order  to  prevent  fermen- 
tation.7 Mountain  sheep  thrive  better  when  fed  on  gorse  than 
on  grass.8  Horses  prefer  it  to  hay  or  even  to  corn,  but  as  it  tends 
to  fatten  them  very  much  it  is  less  suited  for  working  animals. 

1  Stephenson,  J.,  and  Churchill,  J.  M.,  loc.  cit. 

2Woodville,  loc.  cit. 

3  Hogg  and  Johnson,  loc.  cit.  4  Lindley  and  Moore,  loc.  cit. 

5  Pratt,  loc.  cit.  G  Wilson,  loc.  cit. 

7  Fau,  E.,  L'lndustrie  Laitttre  (1910),  No.  42,  pp.  677-679. 

8  Andrews,  loc.  cit. 


USES  OF  WEEDS  203 

In  the  Scilly  Islands  the  ponies  feed  chiefly  on  the  gorse  they 
find  in  the  hills. 

Gorse  is  also  good  for  fuel,  and  in  Cornwall  is  cultivated 
for  the  purpose,  being  chiefly  made  into,  faggots  for  heating 
ovens.  It  burns  rapidly  with  much  heat,  and  was  formerly 
used  in  lime  burning.  The  ashes  are  rich  in  alkali,  and  are 
made  into  lye  or  worked  up  into  balls  with  clay  to  serve  as  a 
substitute  for  soap.1  They  are  also  very  valuable  as  manure, 
particularly  on  peaty  soil. 

Gorse  forms  good  cover  for  game  and  shelter  for  young 
forest  trees,2  and  it  can  also  be  used  for  hedges  if  kept  closely 
trimmed.  It  is,  however,  not  very  resistant  to  frost,  although 
it  will  stand  salt  spray  if  planted  near  the  sea. 

Urtica  dioica  (Common  nettle). — This  much-despised  weed 
has,  in  days  gone  by,  proved  an  exceedingly  useful  friend  to 
mankind.  The  stem  contains  a  large  proportion  of  fibre,  which 
has  been  manufactured  into  every  grade  of  material  from  ropes 
and  cordage  to  fine  white  linen.  It  was  much  used  in  the 
manufacture  of  textile  fabrics  by  the  ancient  Egyptians,2  and 
even  at  the  present  day  supplies  the  inhabitants  of  Siberia  with 
fishing  lines  and  cordage,  while  in  many  villages  of  Piedmont 
it  is  made  into  cloth.  In  1911  an  Austrian  firm  devised  a 
method  of  removing  the  gum  from  the  rough  fibre,  the  result- 
ing finished  product  being  a  pure  bleached  fibre  which  was 
glossy,  supple,  and  flexible.  The  war,  moreover,  has  given  a 
considerable  impetus  to  the  exploitation  of  this  source  of  fibre, 
and  so  many  improvements  and  inventions  have  been  carried 
out  that  it  seems  likely  that,  with  judicious  methods  of  culti- 
vation, nettles  will  prove  a  profitable  crop.  In  1916  the  Central 
Powers  had  developed  the  industry  to  such  an  extent  that 
nettle  fibres  were  reported  to  cost  60  per  cent,  less  than  im- 
ported cotton,  and  the  War  Ministries  were  using  it  for  manu- 
facturing wagon-covers,  tents,  sackings,  clothing  materials,  and 
even  cloth  for  military  underwear.  In  Denmark  the  nettle  yarn 
has  been  worked  up  with  wool,  with  satisfactory  results.  At 
first  the  warp  was  of  wool,  the  woof  of  yarn  spun  from  nettle 
fibres,  and  the  resulting  fabric,  though  not  so  soft  as  pure 
woollen  cloth,  possessed  considerable  strength  and  was  suitable 
for  men's  clothes.  Later  on  attempts  were  made  to  blend 
the  wool  and  nettle  fibres  in  the  yarn,  as  better  results  were 
expected  from  such  a  combination.3 

1  Johnson,  loc.  cit.  '*  Hogg  and  Johnson,  loc.  cit. 

3 See  Brenchley,  W.  E.  (1919),  "The  Uses  of  Weeds  and  Wild  Plants," 
Science  Progress,  XIV,  No.  53,  pp.  128-129. 


204  WEEDS  OF  FARM  LAND 

Steps  were  taken  to  organise  the  collection  and  culti- 
vation of  nettles,  with  the  result  that  by  1918  it  was 
estimated  that  23,000  hectares  (  =  9292  acres)  would  be 
under  nettle  cultivation  in  Germany,  with  an  estimated  yield 
of  175,000  metric  cwt  of  fibre.  The  cultivation  of  nettles 
has  also  been  encouraged  in  Hungary,  a  special  company 
being  formed  to  further  the  work.  The  plants  will  grow  well 
on  ground  that  is  of  little  agricultural  value,  and  in  some 
plantations  they  have  developed  into  shrubs  as  high  as  a 
man.  In  other  cases  plantations  have  been  formed  on  moor- 
land which  is  unsuitable  for  growing  food  crops,  and  it  is 
claimed  that  by  doing  this  the  land  is  subjected  to  a  process 
of  slow,  natural  cultivation  that  in  time  will  increase  the 
agricultural  value  of  the  land 

Nettles  when  cut  and  dried  can  be  used  as  fodder  for 
domesticated  animals.  The  latter  will  not  touch  the  growing 
plants  because  of  the  stinging  hairs,  but  shortly  after  cutting 
these  hairs  collapse  from  loss  of  water  and  are  then  innocuous. 
Nettles  have  long  been  cultivated  in  Sweden,  as  they  can 
be  grown  on  waste  or  poor  land  and  are  very  resistant  to 
extreme  temperatures.1  One  great  advantage  is  their  rapid 
growth ;  with  judicious  cutting  three  crops  a  year  can  be 
obtained.  Even  where  regular  cutting  is  not  practised  the 
leaves  and  seeds  are  often  collected  and  dried  as  winter  food 
for  fowls.  The  leaves  are  boiled  in  water  to  the  consistency 
of  gruel,  and  are  then  mixed  with  cooked  potato  peelings, 
while  the  seeds  are  added  to  other  food  and  are  found  to 
stimulate  egg  production.  Analyses  made  by  Professor 
Hendrick  2  show  that  nettles  may  be  very  useful  as  feeding 
stuff.  Young  nettles  from  12  to  1 8  inches  high  sampled  in 
May  contain  much  fat  and  ash,  and  as  much  albuminoid 
material  as  linseed  cake.  Older  nettles  cut  in  July  are  more 
fibrous  and  contain  more  soluble  carbohydrates,  but  the  per- 
centage of  nitrogen  is  higher  than  that  in  grasses.  These 
figures  indicate  that  dried  nettles  cut  at  the  flowering  stage 
are  similar  in  analysis  to  hay  made  from  leguminous  crops. 
A  yellow  dye  is  obtained  if  the  roots  are  boiled  with  alum, 
and  the  seeds  when  mixed  with  corn  improve  the  appearance 
of  horses,  and  it  is  said  that  horse  dealers  use  them  to  give  a 

1  Garcia  Santos  (1916),  A  Vinha  Portugueza,  XXXI,  No.  9,  pp.  276-280. 

2  National  Food  Jour,   (nth   Sept.,    1918).      See   also  Jour.   Bd.  Agric., 
Vol.  XXV,  p.  992,  1918. 


USES  OF  WEEDS  205 

lively  air  to  an  animal  before  selling  him.  The  chopped  leaves 
are  supposed  to  increase  egg  production  when  fed  to  poultry.1 
Nettles  also  have  their  value  as  human  food,  the  young 
tops  being  boiled  in  spring  like  spinach.  They  are  used 
very  largely  in  this  way  by  the  peasantry  in  the  West  of 
Ireland.  A  useful  rennet  is  made  by  adding  a  quart  of  salt 
to  three  pints  of  a  strong  decoction  of  nettles.  When  a  table- 
spoonful  is  put  into  a  large  bowl  of  milk  the  latter  readily 
clots,  forming  a  pleasant  beverage,  free  from  any  flavour  of 
nettle.2  If  a  leaky  wooden  vessel  be  rubbed  -with  a  handful 
of  nettle  leaves  the  juice  enters  the  cracks  and  coagulates,  and 
the  leakage  is  repaired,  though  no  hint  is  given  as  to  the 
length  of  time  the  repair  holds  good.  The  leaves  are  also 
placed  on  the  top  of  baskets  of  Kentish  plums  to  preserve  the 
bloom — but  it  is  doubtful  whether  the  nettle  leaves  have  any 
specific  value  in  themselves  or  whether  they  simply  keep  away 
interfering  hands  by  virtue  of  their  stings. 

1  Wilson,  loc.  cit.  2  Pratt,  loc.  cit. 


CHAPTER  XIII. 

POPULAR  AND  LOCAL  NAMES  OF  WEEDS.1 

Achillea  millefolium,  L. — Arrow-root,  bloodwort,  camil,  cam- 
mock,  carpenter-grass,  devil's  nettle,  dog  daisy,  eerie, 
garwe,  girs  (stanch  or  stench),  greenarrow,  hundred- 
leaved  grass,  melefowr,  milfoil,  nosebleed,  old  man's 
mustard,  pepper  (old  man's,  wild),  sanguinary,  sneeze- 
wort,  tansy,  thousand-leaf,  thousand-leaved  clover,  yallow, 
yarrow,  yarroway,  yerrow. 

Aethusa  cynapium>  L. —  Ass-parsley,  dill,  dog-poison,  dog's 
parsley,  false  parsley,  fool's  cicely,  fool's  parsley. 

Agrimonia  eupatoria,  L. — Agrimony,  church-steeple,  cockle 
burr,  egremoine,  egremounde,  garclive,  goosechite,  harvest 
lice,  hemony,  liverwort,  rat-tail,  tansy  (white,  wild). 

Agropyron  repens.     See   Triticum  repens. 

Agrostis  sp. — Cloud  grass. 

Agrostis  alba,  L. — Dun  John,  quick,  spear  grass,  whicks, 
wicks,  fine  John,  florin,  running  twitch,  white  bent 
grass. 

Agrostis  stolonifera^  L. — Bent  grass,  black  grass,  black-top 
grass,  florin-grass,  knotgrass,  orcheston  grass,  orchis 
grass  (?),  quitch,  red  robin,  squitch  grass,  surface  twitch, 
water-grass. 

Agrostis  vulgaris,  L. — Bent,  bent-grass,  black  quitch,  bread- 
and-cheese,  fine  John,  monkey's  grass,  squitch,  tussocks, 
twitch,  water  twitch. 

Aira  caryophyllea^  L. — Mouse-grass,  hairgrass,  silver  hair- 
grass. 

Aira  caespitosa,  L. — Bent  grass,  benton  pry,  bull-faces,  bull- 
front,  bull-hassocks,  bull-pates,  bull  pole,  bull's  forehead, 

1  Many  of  the  names  given  in  this  chapter  have  been  met  with  in  the  course 
of  the  weed  surveys  made  by  the  author  in  different  parts  of  the  country.  The 
majority,  however,  have  been  taken  from 

(a)  Britten,  J.,  and  Holland,  R.  (1886),  "  A  Dictionary  of  English  Plant 
Names  " ; 

(b)  Prior,  R.  C.  A.  (1879),  "  On  the  Popular  Names  of  British  Plants  ". 

206 


POPULAR  AND  LOCAL  NAMES  OF  WEEDS    207 

bull-toppin,  carnation-grass,  flag  (?),  hassock,  huff-caps, 
iron  grass,  sniddle,  sniggle-grass,  snizzle-grass,  tufted 
hairgrass,  tussock  grass,  windlestravvs,  zedge-mocks. 

Ajuga  reptans,  L. — Bugle,  brown  bugle,  dead  men's  bellows, 
herb  carpenter,  helfringwort,  middle  comfrey,  middle 
consound,  sicklewort,  wild  mint,  wood  betony. 

Alchemilla  arvensis,  L. — Argentill,  bowel-hive,  breakstone, 
colickwort,  firegrass,  lady's  mantle,  parsley  breakstone, 
parsley  pert  or  piert,  parsley  vlix,  percepier. 

Alchemilla  vulgaris,  L. — Bear's-foot,  dewcup,  duck's-foot,  great 
sanicle,  lady's  mantle,  lamb's  foot,  lion's  foot,  padelion, 
pedelyon,  syndau. 

Allium  ursinum,  L. — Bear's-garlic,  buckrams,  crow-garlick, 
cow-garlick,  devil's  posy,  garlick,  gipsy  onions,  hog's- 
garlick,  ramps,  rams,  ramsden,  ramsey,  ram's  horns,  ram- 
sons,  rommy  or  roms,  rosems,  stink  plant,  wild  garlick, 
wild  leek. 

Allium  vineale,  L. — Crow  onion,  garlick  (cow,  crow,  wild). 

Alopecurus  agrestis,  L. — Bennet-weed,  black  bent,  black  couch, 
black-grass,  black  quitch,  black  squitch  grass,  grass  (spear, 
twitch),  hunger-grass,  hunger-weed,  land-grass,  mouse-tail, 
slender  fox-tail. 

Alopecurus  geniculatus,  L. — Black-grass,  blue-grass,  elbowit- 
grass,  flote-grass,  marsh  foxtail. 

Anagallis  arvensis,  L. — Bird's  eye,  bird's-tongue,  female  pim- 
pernel (var.  ccerulea),  John-go-to-bed-at-noon,  male  pim- 
pernel, merecrop,  orange  lily  pernel,  pimpernel,  poor 
man's  weather-glass,  shepherd's  calender,  shepherd's 
clock,  shepherd's  delight,  shepherd's  glass,  shepherd's 
sundial,  shepherd's  warning,  shepherd's  watch,  shepherd's 
weatherglass,  sunflower,  torn  pimpernowl,  waywort, 
weather  glass,  wincopipe,  wink-a-peep. 

Anthemis  arvensis,  L. — Corn  chamomile,  dog's  camomile  (?), 
white  gowlan. 

Anthemis  cotula,  L. — Balder  brae,  baldeyebrow,  camomile 
(dog's  or  stinking),  camovyne,  daisy  (dog  or  horse),  dog- 
banner,  dog-binder,  dog-fennel,  dog-finkle,  flowan,  hog's 
fennel,  jayweed,  madder,  madenwede,  maise,  maithen, 
mather,  marg,  mathes,  mayweed,  morgan,  murg,  poison 
daisy. 

Anthriscus  sylvestris,  Hoffm. — Ass-parsley,  badman-oatmeal, 
bun,  caxes,  chervil  (cow-weed,  mock  or  wild),  cicely,  cis- 
weed,  coney-parsley,  cow-mumble,  cow-parsley,  cow-weed, 


208  WEEDS  OF  FARM  LAND 

da-ho,  deil's  meal,  deil's  or  devil's  oatmeal,  devil's  parsley, 
dill,  dock  (kadle  or  kettle),  dog-parsley,  eltrot,  ha-ho,  hare 
parsley,  hemlock,  hi-how,  humlock,  keck,  kedlock,  kee- 
shion,  kelk  or  kelks,  kellock,  kesk,  kewsies,  mayweed, 
naughty  man's  oatmeal,  orchard  weed,  parsley  (dog's, 
pig's,  sheep's,  wild),  rabbit-meat,  ratsbane,  sweet  ash, 
white-weed,  wild  carraway,  wild  cicely. 

Anthyllis  vulneraria,  L. — Cat's-claws,  crawnels,  Jupiter's  beard, 
kidney  vetch,  lady's  fingers,  luck,  lamb's-toe,  rustic  wound- 
wort,  staunch,  woundwort,  yellow  crow's-foot. 

Antirrhinum  orontium^  L. — Calf-snout. 

Arabis  thaliana,  L. — Thale-cress,  wall-cress. 

Arenaria. — Sand  weed,  sand  wort. 

Arenaria  serpyllifolia,  L. — Chickweed,  thyme-leaved  sandwort. 

Arnoseris pusilla,  Gaertn. — Lamb's  succory,  swine's  succory. 

Arrhenatherum  avenaceum,  var.  tuberosum^  Gilib. — Arnit  or 
arnut,  buck  beards,  button-grass,  couch,  haver-grass,  knot- 
grass, lobbin  grass,  lousy  or  lucie  arnut,  murrick,  onion 
couch,  pearl,  pearl  grass,  quitch,  swine  arnut,  twitch  (butter 
or  button). 

Artemesia  vulgaris,  L. — Apple-pie,  bulwand,  fat  hen,  fellon- 
herb,  French  tobacco,  green  ginger,  mogford,  motherwort, 
muggert,  mugweed,  mugwort,  sailor's  tobacco,  smother- 
wood,  weremod,  wormwood,  wormit. 

Atriplex. — Areche,  blite,  meals,  wild  orach. 

Atriplex  patula,  L. — Arach,  delt-orach,  fat  hen,  lamb's 
quarters. 

Avena  fatua,  L. — Bearded  oat,  drake,  flaver,  haver,  Kentish 
longtails,  poor  oats,  sowlers,  uncorn,  wild  aits,  wild  oat. 

Bartsia  odontites,  L. — Eyebright,  eyebright  cow-wheat,  hen 
gorse,  red  rattle,  sanctuary. 

Bellis  perennis,  L. — Bachelor's  buttons,  bairnwort,  banwood, 
banwort,  bennergowan,  bennert,  bennet,  benwort,  bessy- 
banwood,  billy  button,  boneflower,  bonwort,  briswort, 
bruisewort,  catposy,  cockiloorie,  comfrey,  confery,  cumfirie, 
daiseyghe,  daisy,  daisy  (dog,  shepherd's,  small  or  the 
children's),  dazeg,  dicky  daisy,  ewe-gowan,  gowan,  gowlan, 
hen  and  chickens,  herb  margaret,  less  consound,  March 
daisy,  margaret' s  herb,  May  gowan,  Mary  gowlan, 
marguerite,  maudlinwort,  mother  of  thousands,  primrose, 
silver  penny,  sweep,  sweeps. 

Borago  officinalis^  L. — Beebread,  borage,  burrage,  cool-tankard, 
Langdebeef,  ox-tongue,  star  flower. 


POPULAR  AND  LOCAL  NAMES  OF  WEEDS    209 

Brassica  alba. — Charlock,  kedlock,  kellock,  kerlock,  ketlock, 
senvie,  white  mustard. 

Brassica  campestris,  L. — Bargeman's  cabbage,  charlock,  ket- 
lock, nape,  yellows. 

Brassica  sinapis. — Bastard  rocket,  bazocks,  birdseed,  brassies, 
brassock,  cadlick,  cadlock,  callock,  calves-feet,  carlock, 
chadlock,  charlick,  charlock,  chedlock,  churlick,  corn  cale, 
craps,  curlick,  curlock,  field  kale,  garlic,  garlock,  kadlock, 
kale,  kecklock,  kedlock,  kellock,  kerlock,  ketlock,  kilk, 
kinkle,  mustard  (corn,  wild),  popple,  presha,  or  presha- 
bhwee  or  prushus,  rape,  rough  cadlock,  runch,  rungy, 
scaldrick  scalies,  scallock,  senvie,  shirt,  skedlock,  skeldock, 
skeldick,  skellock,  skellie  or  skillock,  turnip,  warlock,  will 
kail,  wild  kale,  yellow  flower. 

Briza  media,  L. — Amouret,  bird's-eye,  cow-quake,  dadder-grass, 
danglethorn  (?),  dawther,  didder-grass,  diddery-docks, 
dithering-grass,  dodder,  dodder-grass,  doddering-dickies, 
doddering-dillies,  doddering-grass,  doddering-jockies, 
dodderin-Nancy,  doddle-grass,  dothering-dicks,  dothering- 
toms,  earth-quakes,  grass  (fairy,  pearl,  quaker,  rattle, 
shaking,  shiver,  shivering,  swaggering,  totter,  tottering, 
trembling,  waggering),  hay  shakers,  jockey  grass,  lady's 
hair,  maiden-hair,  mountain  flax,  .quack-ducks,  quakers, 
shake  ladies,  shakers,  shivering  jemmy,  sillar  shakle,  siller 
tassels,  silver  ginglers,  silver  shakers,  suisilk,  trembling 
jockies,  thrimlin-jockies,  wag-wanton,  wag-wants,  whacker 
gerse,  wiggle-waggles,  wig-wag  wanton,  wiggle-waggle- 
wantons. 

Bromus  arvensis,  L. — Field  brome. 

Bromus  asper,  L. — Hairy  brome. 

Bromus  mollis,  L. — Blubber-grass,  bob-grass,  bull-grass,  cock- 
grass,  darnel,  duck  havver,  geese-grass,  goose  corn,  goose- 
grass,  haver-grass,  hooded  grass,  lob  or  lob  grass, 
oat-grass. 

Bromus  secalinus,  L. — Cheat,  cheats,  ches-seed  weed,  cock- 
grass,  darnel,  drake,  droke,  drook,  oat  (dravick,  wild), 
rye  brome-grass,  sleepies. 

Bromus  sterilis,  L. — Black-grass,  drake,  drank,  haver-grass, 
oat-grass. 

Calamintha  acinos,  Clairv.—¥>*$\\  (field,  stone,  or  wild),  basil 
balm,  basil  thyme,  corn  mint  (?),  mother  of  thyme,  poley 
mountain. 


2io  WEEDS  OF  FARM  LAND 

Camelina  sativa,  Cr. — Camline,  cheat,  Dutch  flax,  gold  of 
pleasure,  myagrum,  oil-seed. 

Capsella  bursa-pastoris,  L. — Bad  man's  oatmeal,  blind-weed, 
case-weed,  clappedepouch,  cocowort,  fat  hen,  lady's  purse, 
mother's  heart,  naughty  man's  plaything,  pepper-and-salt, 
.  pick-pbcket,  pick-purse,  pick-your-mother's-heart-out,  poor 
man's  parmacetty,  sanguinary,  shepherd's  bag,  shepherd's 
pouch,  shepherd's  purse,  shepherd's  scrip,  tooth-wort, 
toywort,  ward-seed,  witches'  pouches. 

Carda mine  pratensis,  L. — Apple-pie,  bird-eye,  bird's-eye,  bitter 
cresses,  bogspinks,  bonny-bird-een,  bread-and-milk,  canter- 
bury bells,  cuckoo,  cuckoo-bread,  cuckoo-flower,  cuckoo- 
pint  or  pintle,  cuckoo-spit,  cuckoo's  shoes  and  stockings, 
gookoo-buttons,  gookoo-flower,  headache,  impatient  cress, 
lady  flock,  lady's  glove,  lady's  milksile,  lady's  smock,  lamb 
lakins,  lucy  locket,  may  blob,  may  flower,  meadow, 
meadow  cress,  medetarde,  milkgirl,  milkmaid,  milksile, 
paigle,  pigeon's  eye,  pig's  eyes,  pink,  shoes  and  stockings, 
smell  smock,  smick  smock,  spink,  whitsuntide  gilliflower. 

Carduus  nutans,  L. — Queen  Ann's  thrissel,  thistle  (bank,  buck, 
dog,  musk,  Scotch). 

Carex. — Ae-pointed-gairss,  carnation-grass,  cegge,  grass  (blue, 
hard,  spear,  sour,  spire,  star,  sword),  lesch,  ling,  moor- 
pawms,  pry,  rush,  sag,  sedge,  seggin,  seggs,  serge,  sniddle, 
zeg. 

Carex  glauca^  L. — Carnation-grass,  gilliflower- grass,  glaucous 
sedge,  grass  (pigeon's,  pink),  pry. 

Carex  hirta,  L. — Carnation-grass,  goose-grass,  hairy  sedge, 
hammersedge. 

Carex  vulpina,  L. — Fox  sedge. 

Caucalis  nodosa^  Scop.  — Knotted  hedge  parsley. 

Centaurea  nigra,  L. — Bachelor's  buttons,  ballweed,  belweed, 
black  centaury,  black  soap,  blue  tops,  boleweed,  bolwes, 
bowweed,  bowwood,  bullweed,  bunds,  bundweed,  bunk, 
button-weed,  centaury,  centaury  (great  or  more),  churl's- 
head,  clobweed,  club-weed,  cnop-wort,  cock-heads,  cod- 
weed,  crop-weed,  darbottle,  drumstick,  hardhead,  hardhead 
horse,  hard-iron,  hare-bottle,  harsh-weed,  horse  hardhead, 
horse  knobs,  horse  knops,  horse  knot,  horse-snap,  hurt- 
sickle,  hyrnehard,  iron-heads,  iron-weed,  knapweed,  knob- 
weed,  knop-weed,  knotgrass,  knotweed,  lady's  cushion, 
loggerheads,  matfellon,  shaving-brush,  sweeps,  tarbottle, 
tassel,  yronhard. 


POPULAR  AND  LOCAL  NAMES  OF  WEEDS    211 

Centaurea  scabiosa,  L. — Bachelor's  buttons,  black-top,  bowwood, 
bunk,  drumstick,  great  horse  knobs,  great  knapweed,  horse 
knobs,  horse  knops,  iren-harde,  knobweed,  knotweed, 
matfellon. 

Cerastium  vulgatum,  L. — Chickweed,  mouse-ear,  mouse-ear 
chick-weed. 

Chenopodium. —  Goose-foot,  meals,  nightshade,  wild  orach. 

Chenopodium  album,  L. — Biacon-weed,  dirtweed,  dirty  Dick, 
dirty  John,  drought-weed,  fat  hen,  frost-blite,  hen-fat, 
Johnny  O'Neele,  lamb's-quarters,  lamb's-tongue,  mails, 
meldweed,  melgs,  midden  myles  or  milies,  milds  or  miles, 
muck-weed,  mutton-tops,  myles,  rag  jag,  wild  spinach 
(pigweed  in  Canada  and  U.S.A.). 

Chrysanthemum  leucanthemum,  L. — Bozzom,  caten-aroes,  cows' 
eyes,  daisy  (big,  bull,  butter,  devil's,  dog,  dun  or  dunder, 
field,  great,  horse,  London,  midsummer,  moon,  ox-eye, 
poor-land,  thunder),  daisy  goldins,  dog-flower,  Dutch 
morgan,  espibawn,  gadgevraw,  gadjerwraws,  girt  ox-eye, 
goode,  gowan  (horse,  large,  white),  horse-pennies,  hoss- 
daisy,  large  dicky  daisy,  magweed,  maudlinwort,  may- 
weed, moon,  moon-flower,  moon-pennies,  moon-penny, 
moonwort,  ox-eye,  poverty  weed,  white  bothen,  white  gold, 
white  gowlan,  white  gull. 

Chrysanthemum  segetum,  L. — Bigold,  boodle,  boswell,  bothem, 
bothen,  botherum,  bothul,  bozzom,  buddle,  budland,  corn 
marigold,  fat  hen,  geal  gowan  or  geal  seed,  gil  gowan, 
gold,  golden  corn-flower,  golding,  goldings,  goles,  golland, 
gool  or  goold,  gould,  gouls,  gowan  (gule,  yellow),  gowlan, 
gowland,  guild,  guile,  gule,  manelet,  marigold,  marigold 
(field,  wild),  marigold  goldings,  marigold  goldins,  moon  or 
moons,  ox-eye,  ruddes,  sunflower,  tansy,  yellow  bottle, 
yellow  gold,  yellow  gowans,  yellow  gull,  yellow  ox-eye. 

Cichorium  intybus,  L. — Bunk,  chicory,  succory,  wild  cicory. 

Cirsium  acaule,  Web. — Dwarf  thistle,  ground  thistle,  pod-thistle, 
stemless  thistle. 

Cirsium  arvense,  Scop.  —  Creeping  thistle,  dashel,  dodger, 
thistle  (boar,  corn,  cursed,  dog,  hard,  pricky,  sharp, 
way). 

Cirsium  lanceolatum^  Scop. — Bow  fistle,  bur,  cheese,  dashel, 
marian,  quat  vessel,  thistle  (bank,  bell,  bird,  blue,  boar, 
buck,  bull,  bur,  horse,  Scotch,  spear). 

Cirsium  palustre,  Scop. — Bog-thrissel,  marsh  thistle,  moss- 
thistle,  thistle  (red,  water). 

'4* 


212  WEEDS  OF  FARM  LAND 

Colchicum  autumnale,  L. — Crocus  (autumn,  fog,  meadow, 
michaelmas,  purple),  meadow  saffron,  naked  boys,  naked 
lady,  naked  virgins,  rams,  saffron,  son-before-the-father, 
star-naked  boys,  tube  root,  upstart 

Conium  maculatum,  L. — Bad  man's  oatmeal,  bunk,  cambuck, 
caxes,  heck-how,  hemlock,  herb  bennet,  humlock,  humly, 
keck,  kex,  kelk,  kous,  keish,  kewse,  St.  Bennet's  herb, 
wode-whistle. 

Conopodium  denudatum,  Koch. — Arnit  or  arnut,  badman's  bread, 
catnut,  cipper-nut,  curluns,  deil's  bread,  deil's  oatmeal,  dil- 
note  (?),  earth  chestnut,  earthnut,  ernut,  fare-nut,  gennet, 
gernut,  gourlins,  gowlins,  grunnut,  hawk-nut,  hog-nut, 
hornecks,  Jack  durnils,  jocky  jurnals,  jurnut,  killas,  killi- 
more,  kipper-nut,  knipper-nut,  knotty  meal,  lousy  or  lucie 
arnut,  mandrake,  nut  (ground,  hare,  kipper,  pig,  St. 
Anthony's),  scabby  hands,  swine-bread,  tetter-berry,  truffle, 
yannut,  yarnut,  yennet,  yennut,  yenut,  yor-nut,  yer-nut, 
yowe  yorlings. 

Convolvulus  arvensiS)  L. — Barbine,  barweed,  bearbind,  bell- 
bine,  bellwine,  billy-clipper,  bindweed,  bine,  common  bind, 
corn-bind,  corn-lily,  devil's  guts,  gravel  bindweed,  hedge 
bells,  lap-love,  lily,  lily-bind,  rope-wind,  sheep-bine,  small 
bindweed,  small  withiwind,  wave-wine,  waywind,  weed- 
bind,  weedbine,  wheatbine,  wild  convolvulus,  wind,  wither- 
wine,  withwind  or  withwine. 

Crepis  taraxacifolia,  Thuill. — Beaked  hawk's-beard. 

Crepis  virens,  L. — Smooth  hawk's  beard 

Cuscuta. — Devil's  guts,  dodder,  dother,  fordboh,  laced  thyme, 
strangle-weed. 

Cuscuta  europceay  L. — Beggarweed,  bind,  devil's  guts,  hailweed, 
hairweed,  hale-,  hell-,  or  hairy-bind,  hale-weed,  podder, 
scald,  scald-weed,  strangle-tare. 

Cuscuta  trifolii,  Bab. — Ail-weed,  beggar-weed,   Indian  grass. 

Daucus  carota,  L. — Bee's-nest,  bird's-nest,  crow's-nest,  dawke, 
dill,  fiddle,  field  more  (?),  hill-trot,  mirrot,  rantipole,  wild 
carrot. 

Echium  vulgare,  L. — Blue  bottle,  blue  weed,  blue  cat's-tail, 
bugloss,  cat's-tail,  iron-weed,  langdebeef,  our  Lord's  flannel, 
our  Saviour's  flannel,  snake  flower,  snake's  bugloss,  viper's 
bugloss,  viper's  grass,  viper's  herb,  wild  borage. 

Epilobium. — Herb  willow,  willow  herb. 

Epilobium  hirsutum,  L. — Apple-pie,  blooming  sally,  cherry- 
pie,  coddled  apple,  codlins,  codlings-and-cream,  custard- 


POPULAR  AND  LOCAL  NAMES  OF  WEEDS    213 

cups,  fiddle-grass,  gooseberry  pie,  plum-pudding,  red  withy 
herb,  sod-apple,  son-before-the-father,  wild  willow,  willow 
herb. 

Equisetum. — Cat-rushes,  cat's-tail,  feather,  grandfather's  beard, 
grass  (joint,  scrub,  shave,  water),  holy-water-sprinkle, 
horse-tail,  joint-weed,  mare's-tail,  old  man's  beard,  puddock 
pipes,  pull  pipes,  rattle,  snake  pipes,  tad-broom,  tad  pipes, 
tidy-pipe,  toad  pipe,  wold  man's  beard  (?). 
Equisetum  arvense,  L. — Bottle-brush,  cat's-tail,  colt's-tail,  frog 

pipes,  horse  pipe,  scrub  grass,  shave  grass,  snake  pipes. 
Erigeron  canadense,  L. — Butter-weed,  Canadian  fleabane. 
Erodium. — Heron's-bill. 
Erodium  cicutarium,  LHer. — Needle  (pink,  powk),  stick-pile, 

stork's-bill,  wild  musk. 
Erysimum  cheiranthoides,  Br. — Tarrify,  treacle  mustard,  treacle 

wormseed,  worm-seed. 
Euphorbia. — Spurge,  tithymall. 
Euphorbia  exigua,  L. — Dwarf  spurge. 

Euphorbia  helioscopia,  L. — Cat's-milk,  churnstaff,  deil's  apple- 
trees,  deil's  kirn  staff,  deil's  milk,  devil's  churnstaff,  devil's 
milk,  grass  (wart,  whitlow),  irby-dale  grass,  little  good, 
mad  woman's  milk,  mamma's  milk,  milk  wort,  milk-weed, 
mouse-milk,  Saturday's  pepper,  seven  sisters,  sun  spurge 
or  sun-following  spurge,  turnsole  or  torn-sole,  wartweed, 
wortwort,  wolf's  milk. 
Euphorbia  peplus,  L. — Deil's  milk,  devil's  milk,  petty  spurge, 

seven  sisters,  wartweed,  wee  gweedie. 

Euphrasia  officinalis,  L. — Adhib,  euphrasy,  ewfras,  eyebright. 
Filago  germanica,  L. — Cartafilago,  chafeweed,    childing  cud- 
weed,   clodweed,    cudweed,    cudwort,    downweed,    herb 
impious,  hoarwort,  old  owl,  owl's  crown,  quidwort,  son- 
before-the-father. 

Fumaria  officinalis,  L. — Beggary,  earth-smoke,  fume-of-the- 
earth,  fumiterre,  fumitory,  fumusterre,  God's  fingers  and 
thumbs,  snapdragon,  wax  dolls. 

Galeopsis  tetrahit,  L.  —  Bee-nettle,  blind-nettle,  dai-nettle,  day- 
nettle,  dea-nettle,  de-nettles,  deye-nettle,  dog-nettle,  don- 
ninethell,  female  hems,  glidewort,  hemp  (bastard,  nettle, 
wild),  hemp-nettle,  holyrope,  stinging  nettle,  sting  nettle. 
Galium  aparine,  L. — Airess,  airif,  airup,  aparine,  bedstraw, 
beggar  lice,  beggar  weed,  bleedy  tongues,  bluid  tongue, 
bur,  burhead,  burweed,  catch-rogue,  catch-weed,  chick- 
weed,  claiton,  claver-grass,  cleavers,  cledon,  cleeiton, 


214  WEEDS  OF  FARM  LAND 

cleggers,  clever-grass,  cliden,  clider,  cling-rascal,  clitch- 
button,  elite,  clitheren,  clits,  cliver,  cly,  clyders,  errif, 
geckdor,  geese-grass,  gentlemen's  tormentors,  goosebill, 
goose-grass,  goose-heiriffe,  gooseshare,  goose  tongue, 
gosling  grass,  gosling  scrotch,  gosling  weed,  grass  (scratch, 
scurvy,  Turkey),  grip-grass,  gull-grass,  gye,  hairweed, 
harif,  haritch,  harvest  lice,  hedge-burs,  Jack-at-the-hedge, 
Lizzie-run-the-hedge,  Loveman,  mutton-tops,  pig-tail, 
Robin-run-the-hedge,  Rob-run-up-dyke,  scratch-weed, 
soldiers'  buttons,  stick-a-back,  stickleback,  sweethearts, 
tivers,  tongue-bleeder,  witherspail,  Willy-run-hedge. 

Galium  tricorne^  Stokes. — Rough-fruited  bedstraw. 

Galium  verum,  L. — A-hundred-fald,  bedflower,  bedstraw 
(lady's  or  yellow),  brum,  cheese-rennet,  cliver,  curdwort, 
fleaweed,  fleawort,  gallion,  hundred-fold,  joint  grass, 
keeslip,  lady's  beds,  maiden-hair,  maid's  hair,  our  ladies' 
bedstraw,  petty  mugwet,  rennet,  runnet,  strawbed,  wild 
rosemary,  yellow  goose-grass. 

Genista  tinctoria^  L. — Alleluia,  base  broom,  broom  (dyers'  or 
low),  dyers'  greening  weld,  dyers'  weed,  dyers'  green- 
weed,  dyers'  yellow-weed,  dyeweed,  green  weed,  green- 
wood, widow  wisse,  woad,  woadwax,  woodwax,  wood 
waxen,  wood  wex,  wudwise,  yellows. 

Geranium. — Crane's-bill,  heron's-bill,  shepherd's  needle. 

Geranium  dissectum,  L. — Cut-leaved  crane's-bill,  pink  needle  (?). 

Geranium  \molle,  L.  —  Culverfoot,  dove's-foot,  dove's-foot 
crane's-bill,  pigeon's  foot,  soft  crane's-bill,  starlights. 

Geranium  pratense,  L. — Crowfoot,  crane's-bill,  grace  of  God, 
gratia  Dei. 

Geranium  pusillum,  L. — Smooth  crane's-bill. 

Gnaphalium  uliginosum^  L. — Chafeweed,  cotton  weed,  cudweed, 
marsh  cudweed,  wartwort. 

Her  odeum  sphondylium,  L.  —  Bear's  breech,  bear-skeiters, 
beggar-weed,  bilders,  billers,  broad-leaved  keck,  broad 
kelk,  bunnel,  bunnerts,  bunnun,  buriwand,  caddell,  cad- 
weed,  camlicks,  clogweed,  cow-cakes,  cow-clogweed,  cow- 
keeks,  cow-keep,  cow-mumble,  cow-parsnip,  cushia,  dry 
kesh,  dryland,  scout,  eltrot,  ha-ho,  hardhead,  heltrot, 
hogweed,  keck,  kedlock,  kex,  keglus,  kelk-kecksy,  kesh, 
kesk,  kewsies,  limperscrimp,  lumper-scrump,  madnep, 
meadow  parsnep,  old-rot,  pig's  bubbles,  pig's  cole,  pig's 
parsnip,  pigweed,  piskies,  rabbit-meat,  sweet  biller,  swine 
weed,  skytes. 


POPULAR  AND  LOCAL  NAMES  OF  WEEDS         215 

Hieracium  pilosella,  L. — Erswort  (?),  fellon-herb,  ling  gowlans, 

mouse-ear,  mouse-ear  hawkweed 
Holcus  lanatus,  L  — Dart  grass,  duffel  grass,  grass  (pluff,  rot, 

velvet,  water),  hose  grass,  hose  gerse,  meadow  soft  grass, 

midge-grass,  pussy-cats'-tails,  soft  grass,  white  hayseeds, 

Yorkshire  fog,  Yorkshire  whites. 
Hordeum  pratense,  L. — Rie  grass,  squirrel-tail  grass. 
Hypochaeris  radicata,  L. — Bent,  cat's-ear,  gosmore. 
Juncus. — Rashes,  resh,  rexen,  rish,   rix,  rush,  ryschys,  seave, 

seife  (?),  siv,  thrash,  threshie,  thrush,  thrush-bush. 
Juncus  articulatus,  L. — Shining-fruited  rush,  spart. 
Juncus  bufonius,  L. — Coe  grass,  frog  grass,  toad  grass,  toad 

rush,  saltweed. 

Juncus  communis,  Mey. — Camel's  straw,  common  rush,  floss  (?). 
Juncus  glaucus,  Ehr. — Hard  rush,  resh,  wire  rush. 
Lamium  amplexicaule,  L. — Chickweed,  hen-bit. 
Lamium  purpureum,  L. — Archangel  (red  or  sweet),  badman's 

posies,  black  man's  posies,  day  nettle,  dead  nettle,  deaf 

nettle,  dee  nettle,  dog  nettle,  French  nettle,  nettle,  purple 

dea-nettle,  purple  stinking  archangel  (?),  red  dead  nettle, 

rabbit-meat,  tormentil. 
Lapsana  communis,  L. — Ballagan,  bolgan-leaves,  dock    cress, 

nipple-wort,  succory  dock  cress,  swine's  cress. 
Lathyrus  macrorrhizus,   Wimm. — Bitter  vetch,  caperoilie,  cara- 

meile,  carmele,  carmeil,  carmile,  carmylie,  cormeille,  corr, 

griapperts,  heath  pea,  karemyle,  kipper  nut,   knapperts, 

knipper-nut,  liquory-knots,  mouse  pea,  napperty,  napple, 

thetch,  wood  pea. 
Lathyrus  pratensis,   Z. — Angleberries,    craw-peas,   craw    pea, 

lady's    fingers,  mouse  pea,  tare-everlasting,  torn  thumb, 

vetchling,  yellow  chickling  vetch,  yellow  fitchling,  yellow 

meadow  vetchling,  yellow  tar  fitch. 
Legousia  hybrida,  Del. — Corn  campanula,   corn  violet,  venus 

looking-glass. 

Leontodon  autumnalis,  L. — Autumnal  hawkbit,  garkin  pissabed. 
Leontodon  hispidus,  L. — Rough  hawkbit. 
Linaria*elatine,  Mill. — Cancerwort,  cankerwort,  female  fluellin, 

pointed  fluellen,  speedwell. 

Linaria  minor,  Mill.  —  Jack-by-the-hedge,  small  toadflax. 
Linaria  spuria,  Mill. — Cancerwort,  cankerwort,  female  fluellin. 
Linaria  vulgaris,  Mill. — Bride-weed,  butter-and-eggs,  buttered 

haycocks,  chopt  eggs,  churnstaff,  doggies,  dragon-bushes, 

eggs-and-bacon,    eggs-and-butter,    eggs-and-collops,    flax 


216  WEEDS  OF  FARM  LAND 

(toad,  wild,  yellow  toad),  flaxweed,  gall  wort,  larkspur, 
lion's  mouth,  monkey  flower,  pattens  and  clogs,  rabbits, 
snapdragon,  yellow  (or  yaller)  rod. 

Linum  catharticum,  L. — Fairy  flax,  fairy  lint,  flax  (dwarf, 
mountain,  purging),  laverock's  lint,  mill-mountains. 

Lithospermum  arvense,  L. — Bastard  alkanet,  corn  gromwell 
lichwale,  painting  root,  pearl-plant,  salfern. 

Lizula  campestris,  Willd. — Blackcaps,  chimney-sweeps,  crow- 
feet, cuckoo  grass,  davie-drap,  field  woodrush,  God's 
grace,  Good  Friday  grass,  grass  (black-head,  peeseweep), 
hair-beard,  smuts,  sweeps,  sweeps'  brushes,  sweet  bent 

Lolium  temulentum,  L. — Bragge,  cheat,  cockle,  darnel,  dornel, 
dragge,  drake,  drank,  dravick,  droke,  drunk,  drunken 
plant,  eaver,  ivray,  jum,  lover's  steps,  ray,  riely,  rivery, 
sturdy. 

Lychnis  alba,  Mill. — Bachelor's  buttons,  bull-rattle,  cockle, 
cow-mack,  cow-rattle,  cuckoo-flower  (white,  wild),  grand- 
mother's nightcap,  plum-puddings,  snake  flower,  snake's 
flower,  thunder  bolts,  thunder-flower,  white  bachelor's 
buttons,  white  campion,  white  robin. 

Lychnis  dioica,  L. — Adder' s-flower,  bachelor's  buttons,  billy 
button,  bird's  eye,  brasselty-buttons,  brid-een,  bull's  eye, 
cock-robin,  crowsope,  cuckoo,  cuckoo-flower,  devil's  flower, 
flea-bites,  geuky-flower,  gramfer-greygles,  hare's  eye, 
jack-by-the-hedge,  lousy  beds,  lousy  soldiers'  buttons, 
mother-dee,  plum-puddings,  poor  robin,  ragged  robin, 
red  bachelor's  buttons,  red  bird's  eye,  red  butcher,  red 
campion,  red  jack,  robin  or  robins,  red  robin,  robin 
flower,  robin  hood,  robin-in-the-hose,  robin  i'  th'  hedge, 
robin  red-breast,  robin's  eye,  round  robin,  scalded  apple, 
soldiers,  water  poppies,  wild  geranium,  wild  rose  campion. 

Lychnis  Flos-cuculi,  L. — Bachelor's  buttons,  cock's-caim, 
cock's-comb,  crow-flower,  cuckoo,  cuckoo-flower,  cuckoo 
gilliflower,  fair  maid  of  France,  Indian  pink,  marsh-gilli- 
flower,  meadow  campion,  meadow  pink,  meadow  spink, 
pleasant-in- sight,  ragged  jack,  ragged  robin,  robin  hood, 
rough  robin,  wild  williams. 

Lychnis  githago,  Lam. — Bachelor's  buttons,  cockle,  corn 
campion,  corn  cockle,  cockweed,  corn-flower,  corn  pink, 
drawk,  field  nigella,  gith,  gye,  hardhead,  nele,  papple, 
pawple,  pink,  popille,  popple,  poppy,  ray,  wild  savager. 

Lycopsis  arvensis,  L. — Bugloss,  field  alkanet,  sheep's  tongue. 


POPULAR  AND  LOCAL  NAMES  OF  WEEDS    217 

Lysimachia  nummularia,  L. — Creeping  jenny,  herb  twopence, 
meadow-runagates,  money-wort,  motherwort,  strings  of 
sovereigns,  twopence,  twopenny  grass,  wandering  jenny, 
wandering  sailor. 

Matricaria  chamomilla,  L. — Camomile  (dog's,  German  or 
wild),  deil's  apple-riennie,  dog's  camovyrie,  horse  gowan, 
maithe,  mather,  maudlin,  mayweed,  whitewort. 

Matricaria  inodora,  L. — Camomile  (dog's  or  unsavoury), 
camomile  goldins,  daisy  (dog,  horse),  dog's  camovyne, 
dog  gowan,  mayweed,  scentless  mayweed,  white  gowlan. 

Medicago  lupulina,  L. — Black  grass,  black  medick,  black  none- 
such, black  seed,  black  trefoil,  cinquefoil,  clover,  clover 
(horned  or  yellow),  croyd,  hop,  hop  clover,  hop  medick, 
hop  trefoil,  lamb's-toe,  melilot  trefoil,  natural  grass,  none- 
such, sanfoin,  shamrock,  snail  trefoil,  trefoil. 

Melilotus  officinalis,  L. — Clover  (hart's,  king's,  or  plaister), 
heartwort,  king's  crown,  melilot,  whuttle  grass,  wild 
laburnum. 

Mentha  aquatica,  L. — Baulme  mint  (?),  bishop's  weed,  bishop's 
wort,  fish  mint,  water  mint. 

Mentha  arvensis,  L. — Corn  mint,  field  mint,  lamb's  tongue, 
wild  pennyroyal. 

Myosurus  minimus,  L. — Bloodstrange,  mouse- tail. 

Mysotis  arvensis,  L.—  Bird's  eye,  blue  mouse-ear,  forget-me-not. 

Mysotis  palustris,  L. — Bird's  eye,  catter-pillars,  forget-me-not, 
love-me,  mouse-ear,  scorpion  grass,  snake  grass. 

Mysotis  versicolor.  — Forget-me-not. 

Nepeta  glechoma. — Alehoof,  allhoove,  allhose,  alliff,  bird's  eye, 
blue  runner,  cat's-foot,  deceivers,  devil's  candlesticks, 
fat  hen,  foalfoot,  folesfoth,  gell,  gill,  gill-ale,  gill-creep-by- 
ground,  gill-go-by-ground,  groundavey,  ground  ivy, 
hayhofe,  haymaiden,  hay-maids,  hedge-maids,  heihow, 
hen  and  chickens,  heyhove,  hove,  jenny-run-ith-ground, 
jill,  lion's  mouth,  lizzie-run-the-hedge,  maiden-hair, 
mould,  nip,  robin-run-the-hedge,  rob-run-up-dyke,  run- 
away-jack, runnidyke,  tudnoore,  tunhoof,  turnhoof. 

(Enanthe  pimpinelloides,  L. — Earth-nut,  pig-nut. 

Ononis  arvensis,  L. — Bomariskie,  cammock,  cammock  whin, 
cat  whin,  chamock,  fin,  finweed,  ground  furze,  harrow 
rest,  hen  gorse,  horse's  breath,  lady-whin,  lewte,  petty 
whin,  ramsey,  rastylbow,  rassels,  rest-harrow,  rust-burn, 
sidfast,  sitfast,  Spanish  root,  stainch,  stay-plough,  stinking 
tarn,  wild  liquorice. 


2i8  WEEDS  OF  FARM  LAND 

Orchis  maculata,  L. — Adam-and-eve,  adder's  grass,  baldberry, 
crawfoot,  crowfoot,  dead  man's  ringers,  dead  man's  hands, 
hand  orchis,  hens,  hen's  combs,  lover's  wanton,  man 
orchis,  nightcap,  red-lead,  spotted  orchis. 

Orchis  mascula,  L. — Aaron's  beard,  Adam-and-Eve,  adder's- 
grass,  adder's-tongue,  ballock  grass,  beldairy,  bloody 
butchers,  bloody  ringers,  bloody  man's  finger,  bloody 
man's  hands,  bulldairy,  bull's-bags,  bull-seg,  candlegostes, 
cling-fingers,  cock-flowers,  cock's  kames,  cowslip,  crake- 
feet,  craw-feet,  crawfoot,  craw-tees,  cross-flower,  crow- 
feet, crow-foot,  cuckoo,  cuckoo-flower,  cuckoo  orchis, 
cuckoo-pint,  culverkeys,  dag-stone,  dead  man's  fingers, 
dead  man's  hand,  dead  man's  thumb,  dog's-dogger,  dog- 
stones,  drake's-feet,  fool's  stones,  foxstones,  frogwort, 
gandergoose,  gander-gosses,  gandigosling,  Gethsemane, 
geuky-flower,  giddy  gander,  goat-stones,  goosie-gander, 
gowk  meat,  gramfer-greygles,  greygles,  gussets,  Johnny- 
cocks,  keatlegs,  kettle  case,  kettle-pad,  king-finger,  lady's 
fingers,  long  purples,  man  orchis,  nightcap,  paddock's 
spindle,  poor  man's  blood,  priest's  pintle,  purples,  rag- 
wort, red  butcher,  red  granfer  gregors,  red-lead,  ring- 
finger,  salep,  scabgowks,  single  castle,  single-guss,  skeat- 
legs,  snake  flower,  soldier's  jackets,  spreespinkle,  stander 
grass,  stannen-gusses. 

Orchis  mono,  L. — Beldairy,  bleeding  willow,  bull's  bags,  bull- 
segg,  cuckoo,  cuckoo-flower,  dandy  goshen,  dead  man's 
fingers,  fool's  ballocks,  fool's  stones,  frogwort,  gander- 
gosses,  goose  and  goslings,  green-veined  orchis,  green- 
winged  orchis,  king-finger,  king-fisher,  man  orchis,  nuns, 
parson's  nose,  puddock's  spindles,  rams  horns,  red-lead, 
single  castle. 

Ornithogalum  pyrenaicum,  L. — Asparagus  (Bath,  French, 
Prussian,  or  wild),  French  grass,  French  sparrow-grass, 
sperage,  spiked  star-of-Bethlehem. 

Ornithopus  perpusillus,  L. — Bird's-foot,  fowl-foot. 

Orobanche. — Broom-rape,  choke-fitch,  choke-weed,  herb-bane, 
kill-herb,  strangle-tare,  strangle-weed. 

Orobanche  major,  L. — Orobstrangler,  Our  Lady  of  New 
Chapel's  flower,  tall  or  great  broomrape. 

Papaver  argemone,  Z. — Cock's  head,  headache,  pale  poppy, 
rough-head  poppy,  small  poppy,  wind  rose. 

Papaver  dubium,  L. — Blaver,  blind  eyes,  cock's-head,  headache, 
long-headed  poppy,  yedwark, 


POPULAR  AND  LOCAL  NAMES  OF  WEEDS        219 

Papaver  hybridum,  L. — Rough  poppy. 

Papaver  rhceas,  L. — Blind  eyes,  blindy-buffs,  bledewort, 
canker,  canker  rose,  cheesebowl,  chesbow,  cockeno,  cock- 
rose,  cock's-comb,  cock's-head,  collinhood,  copper-rose, 
coprose,  corn  rose,  corn-flower,  corn  poppy,  cuprose,  cusk, 
darnel,  ear-aches,  fire-flout,  gye,  headache,  headwarke, 
joan  silverpin,  lightnings,  maws,  poison  poppy,  pope, 
popple,  poppy,  puppy,  redweed,  ridweed,  soldiers, 
thunder  bolts,  thunder  flower,  wild  poppy,  yedwark. 

Pedicularis  sylvatica,  L. — Cock's-comb,  dead  men's  bellows, 
honeysuckle,  lousewort,  red  rattle. 

Pimpinella  saxifraga,  L. — Bennet,  breakstone,  burnet  saxifrage, 
old  man's  plaything,  pimpernel,  saxifrage,  self-heal. 

Plantago  coronopus,  L. — Buck's-horn,  buck's-horn  plantain, 
crow-foot,  hartshorn,  hartshorn  plantain,  herb  eve,  herb 
ive,  star  of  the  earth. 

Plantago  lanceolata,  L. — Bent,  black  bent,  black  jacks,  carl- 
doddie,  chimney-sweeps,  clock,  cock-fighters,  cocks,  cocks- 
and-hens,  cock's-head,  curl-doddy,  dog's-rib,  grass  (cock, 
rib,  ripple),  hardhead,  headman,  jackstraws,  kemps, 
kempseed,  knockheads,  lamb's-tongue,  lancell,  leechwort, 
long  plantain,  plantain,  ramstongue,  rat-tail,  rib-wort, 
rib-wort  plantain,  soldiers,  soldier's  tappie,  tinker-tailor 
grass,  windles. 

Plantago  major,  L. — Bent,  birdseed,  bird's  meat,  broad  leaf, 
canary-seed,  carl-doddie,  curl-doddy,  great  plantain,  great 
waybrede,  healing  blade,  kemps,  lamb's-foot,  plant,  plan- 
tain, rat-tail,  ripple  girs,  slanlas,  warba  leaves,  wabert-leaf, 
wayberan-leaf,  waybread,  wayfaring  leaf,  way fron,  wayside 
bread,  waybred,  white  man's  footprint,  wibrow,  wybrow. 

Plantago  media,  L. — Fire-leaves,  fire- weed,  healing  herb,  hoary 
plantain,  lamb's-tongue. 

Poaannua,  L. — Annual  meadowgrass,  cause-way  grass,  Suffolk 
grass. 

Polygala  vulgaris,  L. — Cross-flower,  four  sisters,  gang  flower, 
milkwort,  procession  flower,  robin's  eye,  rogation  flower. 

Polygonum  aviculare,  L. — Allseed,  arm  strong,  beggar- weed, 
bird's  knotgrass,  bird's-tongue,  black  strap,  bloodwort, 
centinode,  cow  grass,  crab  grass,  crab-weed,  cumberfield, 
doorweed,  finzach,  grass  (iron,  knot,  pig,  swine's,  wire), 
hogweed,  knotgrass,  knotwort,  mantie,  nine  joints,  ninety- 
knot,  pig-rush,  pig-weed,  pink-weed,  red-legs,  red  robin, 
redweed,  sparrow-tongue,  stone-weed,  surface  twitch, 


220  WEEDS  OF  FARM  LAND 

swine-carse,    swine's   skir,  tacker-grass,   way-grass,  wire- 
weed. 

Polygonum  convolvulus,  L. — Bearbind,  bed  wine,  bethwine, 
bindcorn,  bindweed,  bindweed  (black,  corn,  or  ivy)  black 
withiwind,  bunwede,  climbing  buckwheat,  cornbind, 
devil's  tether,  dodder,  hay-gob,  lap-love,  lily,  spades, 
weedwind,  wild  hop,  windweede,  withwind,  withwine. 

Polygonum  lapathifolium,  L. — Pale  willow-weed,  willow-weed. 

Polygonum  per sicaria,  L. — Crab  grass,  crab's  claw,  cronesanke, 
dead  arsesmart,  lakeweed,  lover's  pride,  morub,  peach- 
wort,  persicaria,  red  legs,  red  shank,  red-weed,  sauch-weed, 
saucy  Alice,  spotted  arsesmart,  Virgin  Mary's  pinch, 
willow-weed. 

Potentilla  anserina,  L. — Argentina,  argentine,  blithran,  butter- 
cup, camoroche,  fair  days,  fair-grass,  goose-grass,  goose 
tansy,  helde,  marsh  corn,  mascorns,  midsummer  silver, 
moor-grass,  moors  moss-crops,  silver  feather,  silver-weed, 
silvery  cinquefoil,  tansy,  tansy  (dog's,  wild),  traveller's 
ease,  wild  agrimony. 

Potentilla  reptans,  L. — Cinquefoil,  fiflef,  five-finger-blossom, 
five-finger-grass,  five-fingers,  five-leaf,  five-leaved  grass, 
golden-blossom,  herb  five-leaf,  sinkfield,  synkefoyle,  tor- 
mentil. 

Potentilla  tormentilla,  Sibth. — Biscuit,  blood-root,  earth  bark, 
ewe  daisy,  five-fingers,  flesh-and-blood,  septfoil,  setfoil, 
seven-leaves,  shepherd's  knot,  shepherd's  root,  sheep's 
knapperty,  thormantle,  tormentil,  turmentille. 

Poterium  sanguisorba,  L. — Burnet,  pimpernel,  pimpinell,  salad 
burnet. 

Primula  verts,  L. — Artetyke,  bird's-eye,  cooslip,  coostropple, 
couslop,  cow-paigle,  cowslap,  cowslek,  cowslip,  cowslip 
primrose,  cowslop,  cow's-mouth,  cow-paigle,  cow-stripling, 
cow-stropple,  crewel,  culverkeys,  fairy  cups,  galligaskins, 
gaskins,  herb  paralysy,  herb  Peter,  horse  buckles,  lady's 
fingers,  lady  keys,  may  flower,  paigle,  palsywort,  paraly- 
sis, passwort,  Peter,  petty  mullein,  plaggis,  plum-rocks, 
St.  Peterwort. 

Prunella  vulgaris,  L. — All-heal,  brown-wort,  brunel,  bumble 
bees,  carpenter  (herb,  proud),  carpenter-grass,  carpenter's 
herb,  fly  flowers,  heart  of  the  earth,  hook-heal,  London 
bottles,  pick  pocket,  pimpernel,  prince's  feather,  prunell, 
self-heal,  sicklewort,  slough-heal,  touch  and  heal. 
Ranunculus  acris,  L. — Bachelor's  buttons,  baffiners,  bassinet, 


POPULAR  AND  LOCAL  NAMES  OF  WEEDS        221 

blister-plant,  bolt,  butter  creeses,  buttercup,  butter  daisy, 
butter-flower,  butter  rose,  carlock-cups,  clovewort,  cow- 
slip, craw-foot,  craw-taes,  crazy,  crow-flower,  crow-foot, 
crow-pightle,  crow's-foot,  crowtoe,  eggs-and  -butter,  gil- 
CUP>  g°ld  crap,  gold  cup,  gold  knops,  golden  knobs,  goldy 
knob,  guilty-cup,  horse  gold,  king-cup,  king's  knob, 
paigle,  yellow  bachelor's  buttons,  yellow  caul,  yellow 
crees,  yellow  cups,  yellow  gowan,  yellow  gowlan. 

Ranunculus  arvensis,  L. — Corn  buttercup,  crow-foot  (corn  or 
urchin),  crow's-claws,  devil-on-all-sides,  devil-on-both- 
sides,  devil's  claws,  devil's  coach  wheel,  devil's  currycomb, 
dill- cup,  English  stavesacre,  forking  robin,  gold-weed, 
gye,  hard-iron,  hedge-hog,  hell  weed,  horse  gold,  horse- 
gould,  hunger- weed,  Jack-o'-both-sides,  jack-weed,  joy, 
peagle,  pricklebacks,  scratchbur,  starveacre,  yellow  crees, 
yellow  cup. 

Ranunculus  bulbosus,  L. — Baffiners,  bassinet,  bolt,  buttercup, 
butter  creeses,  butter  daisy,  butter-flower,  carlock-cups, 
craw,  craw-crowfoot,  crazy,  crow-flower,  crowfoot,  crow- 
pightle,  crow's-foot,  crowtoe,  cuckoo-buds,  eggs-and- 
butter,  gil-cup,  gold  crap,  gold  knobs,  golden  knobs, 
golden  cup,  goldy  knob,  guilty-cup,  hillcups,  horse  gold, 
king-cob,  king-cup,  king's  knob,  lode-wort,  paigle, 
pissabed,  rape  crowfoot,  St.  Anthony's  rape,  St.  An- 
thony's turnip,  yellow  crees,  yellow  caul,  yellow  cups, 
yellow  gowlan. 

Ranunculus  hirsutus,  Curtis. — Pale  hairy  crowfoot. 

Ranunculus  repens,  L. — Baffiners,  bassinet,  bolt,  butter  creeses, 
buttercup,  butter  daisy,  butter-flower,  carlock-cups,  cat- 
claws,  craw-foot,  craw-taes,  crazy,  creeping  buttercup, 
crow-feet,  crow-flower,  crow- foot,  crow-pightle,  crow's- 
claws,  crow's-foot,  crow-toe,  devil's  guts,  gold-balls,  gold 
crap,  gold  knops,  golden  cup,  goldy  knob,  granny-threads, 
guilty-cup,  hod-the-rake,  horse  gold,  king-cup,  lantern 
leaves,  meg- many-feet,  paigle,  ram's  claws,  sitfast,  sitsicker, 
tether-toad,  toad-tether,  yellow-caul,  yellow  crees,  yellow 
cups,  yellow  gowlan. 

Raphanus  raphanistrum,  L. — Cadlock,  charlock,  charlock 
(jointed  or  white),  crawps,  curlock,  kedlock,  kellock, 
ketlock,  rabone,  rump,  runch,  skeldock,  skeldick,  skellie, 
skellock,  skillock,  warlock,  wild  mustard,  wild  radish. 

Reseda  lutea,  L. — Base  dyer's  weed,  base  rocket,  crambling 
rocket,  wild  mignonette,  yellow  reseda. 


222  WEEDS  OF  FARM  LAND 

Rhinanthus  crista-galli,  L. — Clock,  cock -grass,  cock's-comb, 
cow-wheat,  dog's  siller,  fiddle-cases,  gowk's  sixpence, 
grass  (penny,  rattle),  hen  pen,  henny  penny,  hen's  combs, 
honeysuckle,  horse  pens,  locusts,  meadow  rattle,  money, 
money  grass,  pence,  penny  rattle,  penny  weed,  rattle, 
rattle-bags,  rattle-box,  rattle-penny,  rochlis,  rottle-penny, 
snaffles,  yellow  meadow  lousewort,  yellow  rattle. 

Rumex. — Dock,  docken,  doodykye,  phorams  or  phorans,  red 
dock. 

Rumex  acetosa,  L. — Bread-and-cheese,  cock  sorrell,  dock  (sharp 
or  sour),  donkey's  oats,  French  sourock,  green-sauce, 
green  sorrell,  lammie  sourrocks,  ranty-tanty  (?),  red  shank, 
sallet,  sarock,  sooracks,  sorrel,  sorrel  (green,  sow),  sorrow, 
sourack,  sour  docken,  sour  grass,  sour  leek,  sour-sabs  or 
sour-suds,  sour  sauce,  sour  sodge,  sourocks,  Tom  Thumb's 
thousand  fingers. 

Rumex  acetosella,  L. — Bread-and-cheese,  cuckoo's  meat,  cuckoo's 
sorrel,  lammie  sourocks,  ranty-tanty,  sheep's  sorrel, 
sheep's  sourack,  sooracks,  soorocks,  sourocks,  sour  dock, 
sour  leek. 

Rumex  conglomerate \  Murr. — Clustered  dock. 

Rumex  crispus,  L. — Curled  dock,  dockum. 

Rumex  obtusifolius,  L. — Batter  dock,  broad  dock,  butter  dock, 
celery-seed,  cushy-cows,  docken,  kettle  dock,  red  shank, 
smair  dock. 

Rumex  sanguineus^  L. — Bloodwort,  bloody  dock,  dock. 

Scabiosa  arvensis,  L. — Bachelor's  buttons,  billy  button,  black 
soap,  blue  buttons,  blue  caps,  blue  men,  broadweed, 
cardies,  clod-weed,  clog-weed,  curl-doddy,  Egyptian  rose, 
gipsy  flower,  gipsy  rose,  lady's  cushion,  pincushion, 
scabious,  scabridge,  scabril. 

Scabiosa  succisa,  L. — Bachelor's  buttons,  blue-ball,  blue-bannets, 
blue  bonnets,  blue  buttons,  blue-caps,  blue-heads,  blue- 
kiss,  blue-tops,  bunds,  bundweed,  carl-doddie,  curl-doddy, 
devil's-bit,  devil's-bit  scabious,  fire-leaves,  forbete,  forebit, 
forebitten  more,  gentlemen's  buttons,  hardhead,  hog-a- 
back, lamb's  ears,  more-herbyw,  ofbit,  remcope,  stinking 
Nancy,  woolly  hardhead. 

Scandix  pecten,  L. — Adam's  needle,  beggar's  needle,  chervil 
(needle  or  wild),  clock-needle,  comb  (lady's,  shepherd's,  or 
venus's),  coombs,  crake-needle,  crow-needle,  crowpecks, 
deil's  or  devil's  darning-needle,  darning  needles,  deil's 
elshin,  elshins,  ground  enell,  hedge-hog,  needle,  old 


POPULAR  AND  LOCAL  NAMES  OF  WEEDS    223 

wife's  darning  needles,  old  woman's  needle,  pink  needle, 
poke  needle,  pook  needle,  poukenel,  pound  needle,  powk 
needle,  puck  needle,  shepherd's  needle,  stikpyle,  tailor's 
needles,  throck-needle,  venus'-needle,  wild  parsley. 

Scleranthus  annuus,  L. — German  knotgrass,  knawel,  knotgrass, 
parsley  pert  or  piert. 

Senebiera  coronopus,  Poir. — Buck's-horn,  cress  (swine's  or  wart), 
grass  (hog,  sow),  hartshorn,  herb  Eve,  herb  ive,  star  of  the 
earth,  wartwort. 

Senecio  jacobcza,  L. — Agreen,  benweed,  bindweed,  binweed, 
booin,  bowens,  bowlochs,  bunnels,  bunwede,  cammock, 
cankerweed,  cheadle-dock,  cowfoot,  cradle-dock,  cushag, 
dock  (kadle,  kettle),  dog-standard,  fairies'  horse,  fellon- 
weed,  fizz-gigs,  fleedod,  fleenurt,  flydod,  grundswaith, 
James'  weed,  James'  wort,  keddle  dock,  marefart,  muggert, 
ragged  Jack,  ragged  Robin,  rag  weed,  rag  wort,  St.  James' 
wort,  scrape-clean,  seggrom,  seggy,  sigrim,  stagger-wort, 
staner-wort,  staver-wort,  stinking  alisander,  stinking  Billy, 
stinking  Davie,  stinking  elshinder,  stinking-weed,  swine's 
cress,  swine's  grass,  tansy,  weeby,  yack-yard,  yark-rod, 
yellow  ellshinders,  yellow-weed. 

Senecio  vulgaris,  L.  —  Birdseed,  chickenweed,  chinchone, 
grinning  swallow,  grinsel,  groundsel,  grunsel,  grundsel, 
grunnishule,  sencion,  simson,  swichen. 

Serratula  tinctoria,  L. — Saw-wort. 

Sherardia  arvensis,  L. — Allison,  dodger,  field  madder,  herb 
sherard,  madderlen,  spurwort. 

Silene  anglica,  L. — English  catchfly, 

Silene  inflata,  L. — Adder-and-snake  plant,  ben,  bird's-eggs, 
bladder  campion,  bletherweed,  bull  rattle,  clapweed, 
cowbell,  cowcracker,  cowmack,  cowpaps,  crackers,  frothy 
poppy,  knap-bottle,  rattle-bags,  snappers,  spading  poppy, 
thunder  bolts,  white  bottle,  white  cockle. 

Silene  noctiflora,  L. — Night-flowering  catchfly. 

Sisymbrium  officinale,  L.  —  Bank  cress,  crambl  ing-rocket, 
hedge  mustard,  hedgeweed,  lucifer  matches,  scrambling 
rocket. 

Solanum  dulcamara,  L. — Awfood,  belladonya,  bittersweet, 
blue  bindweed,  deadly  nightshade,  dogwood,  dwale, 
fellon-wood,  fellonwort,  mad  dog's  berries,  nightshade 
(bittersweet,  wood),  poison-berry,  poison-flower,  poisonous 
tea  plant,  pushion  berry,  robin-run-the-hedge,  skaw-coo, 
snake-berry,  snake's  poison-food,  sweet  bitter,  terri- 
diddle,  terrydivle,  tether  devil,  woody  night-shade. 


224  WEEDS  OF  FARM  LAND 

Solanum  nigrum,  L. — Black  nightshade,  duscle,  garden  night- 
shade, hound's-berry,  mixplenton,  morel,  petty  morel. 

Sonchus  arvensis,  L. — Corn  sowthistle,  dindle,  gutweed,  hog- 
weed,  rosemary,  swine  thistle,  tree  sow  thistle,  langley 
beef. 

Sonchus  oleraceus,  L. — Dindle,  hare's  colewort,  hare's  lettuce, 
hare's  palace,  hare's  thistle,  milk  thistle,  milk-weed,  milky 
dashel,  milky  dickies,  milky  tassel,  St.  Mary's  seed,  sow- 
dingle,  sow  thistle,  swine  thistle,  swinies,  thowthystylle. 

Spergula  arvensis,  L. — Beggar- weed,  bottle  brush,  cowquake, 
dodder,  dother,  farmer's  ruin,  franke,  granyagh,  lousy 
grass,  make-beggar,  mountain  flax,  perry,  pick  pocket, 
pick  purse,  poverty  weed,  sandgrass,  sandweed,  spurry, 
toad  flax,  yarr,  yarrel,  yawr,  yur. 

Spircea  fitipendula,  L. — Dropwort,  fillyfindillan,  lady's  ruffles, 
meadow-sweet,  walwort  (?). 

Spircea  ulmaria,  L. — Bittersweet,  bridewort,  courtship-and- 
matrimony,  goat's  beard,  harif,  honey-sweet,  maid  of  the 
meadow,  maid-sweet,  meadow-soot,  meadow-sweet,  mead- 
wort,  my  lady's  belt,  queen-of-the-meadow,  sweet  hay. 

Stachys  arvensis,  L. — Field  woundwort. 

Stachys  betonica,  Benth. — Betayne,  betony,  bidney,  bishopswort, 
Vetoyn,  wild  hop,  wood  betony. 

Stachys  palustris,  L. — Clown's  all-heal,  clown's  woundwort, 
cock-head,  dead-nettle,  hound's-tongue,  marsh  woundwort, 
rough  weed,  runch,  sheep's  brisken,  swine  arnut,  swine's 
maskert 

Stellaria  graminea,  L. — Heath  speedwell,  star-wort. 

Stellaria  medea,  L. — Chickenweed,  chickenwort,  chickweed, 
chuckenwort,  cickenwort,  craches,  cuckenwort,  flewort, 
hen's  inheritance,  maruns,  tongue  grass,  white  bird's-eye, 
winter-weed. 

Taraxacum  vulgare,  Lam. —  Bitterwort,  blowball,  blower, 
canker,  cankerwort,  clock,  crow-parsnip,  dandelion,  dente- 
lion,  dindle,  doon-head-clock,  fortune-teller,  gowan  (horse, 
witch,  yellow),  grumsel,  Irish  daisy,  lion's  teeth,  male, 
milk  gowan,  monkshead,  one-o'clocks,  pee-a-bed,  pismires, 
piss-abed,  priest's  crown,  stink  davie,  swine's  snout. 

Thlaspi  arvense,  L. — Boor's  mustard,  bowyer's  mustard,  churl's 
mustard,  cress  (penny  or  wild),  dish  mustard,  mithridate 
mustard,  treacle  mustard,  treaclewort. 

Tragopogon  pratensis,  L.  —  Buck's-beard,  gait-berde,  goat's 
beard,  go-to-bed-at-noon,  Jack-by-the-hedge,  John-go-to- 


POPULAR  AND  LOCAL  NAMES  OF  WEEDS    225 

bed-at-noon,  Joseph's  flower,  nap-at-noon,  noon-flower, 
noontide,  shepherd's  clock,  sleep-at-noon,  star  of  Jerusa- 
lem. 

Triticum  repens,  L.  (=  Agropyron  repens,  Beauv.}. — Cooch, 
couch,  couchwheat,  dog-grass,  felt,  grass  (cough,  pearl, 
quick,  quitch,  scutch,  shelly,  skally,  spear,  squitch,  three- 
leaved,  twitch,  wicken),  knotgrass,  lonachies,  needles, 
quick,  quicken,  q wicks,  quitch,  rack,  ronnachs,  runch  (?), 
scryle,  scutch,  shear  grass,  sheep's  cheese,  sheep's  sourack, 
skoil,  squitch,  strap  grass,  stroil,  twike,  twitch,  whickenins, 
whicks,  white  couch-grass,  wick,  wickens,  windlestraws, 
wizzards,  wrack,  yawl. 

Tussilago  farfara^  L. — Ass's  foot,  bull-foot,  clatter-clogs,  clayt, 
clay  weed,  cleats,  clot,  colt-herb,  coltsfoot,  cough  wort, 
coutfit,  cow-heave,  dishalaga,  dove-dock,  dummy  weed, 
floatweed,  foalfoot,  foilefoot,  hog-weed,  hoofs,  horse-hoof, 
horse-hove,  son-before-the- father,  sow  foot,  tushalan, 
tushylucky  gowan. 

Urtica  dioica^  L. — Naughty  man's  plaything,  nettle,  scaddie, 
stinging  nettle,  stingy  nettle,  tenging  nettle. 

Urtica  urens,  L. — Burning  nettle,  dog  nettle  (?),  ettle,  small 
nettle,  stingy  nettle. 

Valerianella  olitoria,  Mcench. — Cornel-sallet,  corn  salad,  lamb's 
lettuce,  milk  grass,  potherb,  white  potherb. 

Veronica  agrestis,  L. — Chickweed,  field  speedwell,  garden 
speedwell,  germander,  germander  chickweed,  germander 
speedwell,  winter-weed. 

Veronica  arvensis,  L. — Corn  speedwell,  wall  speedwell. 

Veronica  chamcedrys,  L. — Angel's-eyes,  astro phell,  base  ver- 
vain, billy  bright-eye,  bird's-eye,  blue  bird's-eye,  blue  eye, 
blewart,  blind  flower,  blue  stars,  bobby's  eyes,  bonny- 
birdee,  cat's-een,  cat's-eyes,  deil's  flower,  English  treacle, 
eyebright,  flat  vervain,  forget-me-not,  germander,  ger- 
mander speedwell,  god's  eye,  lady's  thimble,  love-me-not, 
milkmaid's  eye,  poor  man's  tea,  remember  me,  speed- 
well, wild  germander,  wish  me  well. 

Veronica  hederoefotia,  L. — Bird's  eye,  botherum,  corn  speedwell, 
dotherum,  hen-bit,  ivy  chickweed,  ivy-leaved  speedwell, 
morgeline,  mother  of  wheat,  winter-weed. 

Veronica  serpyllifolia,  L. — Paul's  betony,  thyme-leaved  speed- 
well. 

Veronica  tournefortii,  Gmel. — Bird's-eye,  cat's-eyes,  cuckoo's 
leader,  large  field  speedwell. 

15 


226  WEEDS  OF  FARM  LAND 

Vicia  angustifolia,  L. — Narrow-leaved  vetch. 

Vicia  cracca,  L. — Blue  tar-fitch,  cat-peas,  cow  vetch,  huggaback, 
mice  pea,  tar  grass,  tine,  tine  grass,  tufted  vetch,  twine 
grass,  wild  fetches,  wild  tare,  wild  thetch  grass,  wild  vetch 
or  fitch. 

Vicia  hirsuta,  L. — Bindweed,  dill,  dother,   fitch,   hairy   tare, 

*  lintels,  strangle-tare,   tare,  tar-fitch,  tar  grass,  tar  vetch, 

tine  grass,  tine  tare,  tine-weed,  titters,  wild  thetch  grass. 

Vicia  sativa,  L. — Chichelings,  cichlings,  fatch,  fetch,  fitch, 
fitchacks,  gore-thetch,  lints,  pebble-vetch,  racers,  tar,  tare, 
tere,  thatch,  thetch,  twadgers,  urles,  vatch,  vetch,  wild 
fitch. 

Vicia  sepiumy  L. — Crow-peas,  dill,  hedge  vetch,  tare,  thatch, 
thetch,  twadgers,  vetch,  wild  tare,  wild  vetch. 

Vicia  tetrasperma,  Mcench. — Smooth  tare. 

Viola  tricolor,  L. — Beedy's  eyes,  Biddy's  eyes,  bleeding  heart, 
buttery-entry,  call-me-to-you,  cat's-faces,  cull-me-to-you, 
face-and-hood,  fancy,  flamy,  garden  gate,  godfathers  and 
godmothers,  heartsease,  heart's  pansy,  heart  seed,  herb 
trinity,  jack-behind-the-garden-gate,  jump-up-and-kiss-me, 
kiss-me,  kiss -me -over -the -garden -gate,  Kitty-run-the- 
streets,  leap-up-and-kiss-me,  live-in-idleness,  look-up-and- 
kiss-me,  love-in-idle,  love-in-idleness,  love  true,  meet-her- 
i'-th'-entry-kiss-her-i'-th'-buttery,  monkey's  face,  pance, 
pansy,  paunce,  pensy,  pink-o'-my-John,  stepmother,  three 
faces  in  a  hood,  tickle-my-fancy,  tittle  my  fancy,  two-faces- 
under-the-sun,  violet,  violet  (horse,  trinity),  wild  love  and 
idle. 


AUTHOR  INDEX. 


ADAM,  J.  (1789),  51,  53,  112,  115. 
A.  D.  H.  (igoo),  70. 
Amos,  A.  (1917),  50. 
Anderson,  J.  (1779),  49,  53. 
Andrews,  G.  H.  (1853),  191,  302. 
Anzibor,  S.  (1912),  46. 
Armstrong,  S.  F.  (1907),  176. 

BARTHE,  L.  (1918),  106,  in. 

Bernatsky,  J.  (1915),  193. 

Berry,  R.   A.,   Robinson,  G.   W.,  and 

Russell,  E.  J.  (1918),  199. 
Blith,  W.  (1652),  46. 
Borneman  (1913),  108. 
Brenchley,  W.  E.  (1911),  121. 

(1912),  121. 

(JQIS),  a,  121. 

(1913),  b,  99. 

(1915),  121. 

(1916-17),     107,     112,     121,     183, 

189. 

(1918),  79,  140. 

(1919),  «,  6. 

-  (1919),  b,  203. 
Britten,    J.,    and   Holland,    R.    (1886), 

206. 
Buckman  (1855),  *39>  *45,  152. 

CARRUTHERS,  W.  (1906),  66. 

Clark,  G.  H.,  and  Fletcher,  J.  (1909),  4, 

12. 

Cockayne,  A.  H.  (1915),  70. 
Collinge,  W.  E.  (1913),  28,  75. 

(1914),  28. 

Cox,  H.  R.  (1915),  68. 

—  (1918),  114. 

Crichton  Browne,  J.  (1917),  193. 
Culpepper,  189. 
Cushny,  A.  R.  (1918),  192. 

DEGEN,  A.  (1916),  105. 
Dorph  Petersen  (1910),  74. 
Dusserre,  C.  (1916),  60. 

EVERSHED,  A.  F.  C.  H.  (1918),  29. 
Ewart,  A.  J.  (1909),  103,  104,  106,  no, 


FARCY,  J.  (1910),  96. 
Fau,  E.  (1910),  202. 


Fleming,  C.  E.  (1918),  in. 
Fliickiger  and  Hanbury  (1874),  192. 
F.  M.  (1910),  115. 

GARCIA  Santos  (1916),  204. 
Garman,  H.  (1903),  97. 
Gerarde  (1863),  187,  igo,  192. 
Gordon,  G.  P.  (igi6),  65. 
Giimbel,  H.  (igi2),  83. 

HALL,  A.  D.,  and  Russell,  E.  J.  (igii), 

!75- 

Hanasek,  T.  Z.  (1915),  igi. 
Hansen,  K.  (1911),  74. 
Hansen  und  Mez  (1916),  198. 
Hardie,  W.  (1904),  49. 
Henderson,  T.  B.  R.  (igog),  115. 
Hendrick  (1918),  204. 
Henslow,  G.  (1901),  104,  105,  in,  112- 
Hill,  A.  W.  (igi7),  76. 
Hiltner  (igii),  57. 
Hogg,  R.,  and  Johnson,  G.  W.  (1863), 

187-203. 

Houghton  (1728),  201. 
Howitt,  J.  E.  (igi6),  107,  no. 
Hunter,  A.  (1803),  64. 
Hutchison,  H.  P.  (1912),  6g. 

D'IPPOLITO,  G.  (igi3),  gs. 

JAGUENAUD,  G.  (igi2),  59. 
Johnson,  C.  P.  (1861-2),  igo,  ig3,  194, 
201,  203. 

KELLERMAN,  W.  A.  (i8g5),  110. 
Kerner,  A.,  and  Oliver,  F.  W.  (1895), 

Kling,  M.  (1915  ?),  191,  193,  201. 
Knapp,    F.    H.  (1846),   187,   191,   ig3, 
iQ4»  J97.  I98>  201. 

LINDLEY,  J.,  and  Moore,  T.  (i88g),  188, 

igo,  ig4-2O2. 
Long,  H.  C.  (igi2),  50. 

-  (igio),  47,  i3g,  152. 
(igi7),  104,  105,  106,  107,  115. 


MAIDEN,  J.  H.  (igi6),  in. 
Marten,  J.  B.  (igi6),  57. 


227 


228 


WEEDS  OF  FARM  LAND 


McGeorge,  W.  T.  (1915),  59. 
Milburn,  T.  (1916),  65. 
Milne,  D.  (1915),  75. 
Montemartini,  L.  (1913),  94. 
Morettini,  A.  (1915),  59. 

(1914),  75- 

Munerati,   O.,   and    Zapparoli,   T.   V. 
(1913),  78. 

NELSON,  J.  C.  (1917),  12. 

PARKIN,  J.  (1918),  79. 

Parkinson,  J.  (1629),  187. 

Passerini,  N.  (1910),  79. 

Patterson,    H.    J.,   and   White,   H.   J. 

(1912),  74. 
Pliny   (Holland's    Translation,    1864), 

187,  188,  200. 
Pratt,    A.     (n.d.),    187,    191,    193-202, 

205. 
Prior,  R.  C.  A.  (1879),  207. 

RABATE",  E.  (1911),  58. 
Rendle,  A.  B.  (1915),  n. 
(1913),  Si- 


SMITH,  J.  D.  (1917),  in. 
Stapledon,  R.  G.  (1910),  178. 

(1916),  n. 

Stebler  and  Schroeter  (1908),  108. 
Stephenson,  J.,  and  Churchill,  J.    M. 

(1834),  194,  202. 
Strickland,  H.   E.,  Daubeny,  Henslow, 

and  Lindley  (1850,  1857),  72. 

THEOPHRASTUS  (322  B.C.),  192. 

UNDERWOOD,  L.  M.  (1912),  42. 

VOELKER,  J.  A.  (1911),  53,  191. 
(1918),  54- 

WALDRON,  L.  R.  (1904),  78. 
Wilson  (1847),  186,  189-202,  205. 
Woodruffe    Peacock,  E.  A.  (1917),  a, 

17- 

(1917),  b,  28. 

(1918),  16. 

Woodville,  W.  (1790-1792),  188,  191, 
194,  195,  199,  202. 


GENERAL  INDEX. 


Achillea  millefoliitm.     See  Yarrow. 

Acid  soil,  118,  119,  120,  141,  151. 

Adventitious  roots,  88. 

jEthusa  cynapium,  73,  106,  128,  206. 

Agrimonia  eupatoria,  26  (fig.),  188, 
189,  206. 

Agrimony,  25,  26  (fig.),  116,  188,  189, 
206. 

Agropyron  repens.     See  Couch-grass. 

Agrostis.     See  Bent-grass. 

A.  alba,  190,  206. 

A.  stolonifera,  38,  151,  206. 

A.  vulgaris,  206. 

Aira  ccespitosa,  112,  178,  206. 

A.  caryophyllea,  206. 

Ajuga  rep  tans,  207. 

Alckemilla  arvensis.  See  Lady's 
Mantle. 

A.  vnlgaris,  178,  207. 

Alfalfa,  59,  96.     See  also  Lucerne. 

Allium  ursinum.     See  Ramsons. 

A.  vineale.  See  Crow  Garlic  and  Wild 
Onion. 

Alluvial  areas,  177. 

Alopccurus  agrestis,  154.  See  also 
Black  Bent. 

A.  geniculatus,  207. 

A.  pratensis,  27,  75. 

America,  97,  115. 

American  Weeder,  47. 

Ammonium  sulphate,  69. 

Anagallis  arvensis.  See  Scarlet  Pim- 
pernel. 

Animals,  weeds  distributed  by,  23,  74, 

Annual  weeds,  46,  58,  84. 

Anthemis  arvensis.     See  Corn  Chamo- 

mile. 

A.  cotula,  134,  156,  207. 
Anthoxanthum  odoratum,  182. 
Anthriscus      sylvestris.        See      Wild 

Chervil. 

Anthyllis  vulneraria,  187,  208. 
Antirrhinum  orontium,  208. 
Arabis  thaliana,  129,  208. 
Arable  land,  eradication  of  weeds  from, 

46-63. 

—  weeds,  definition  of,  2. 
in  grass  fields,  16. 


Arctium  lappa,  73. 

Arenaria  serpyllifolia.     See  Sandwort. 
Arnoseris  pusilla,  208. 
Arrhenatherum  avenaceum,  27,  208. 
A.    avenaceum  var.   tuberosum,  39,   41 

(fig-)- 

Arrowhead,  178. 
Arsenite  of  soda,  59,  67,  96. 
Artemesia  vnlgaris,  208. 
Asparagus,   Bath,  91,    196.     See   also 

Ornithogalum,  pyrenaicum. 
Assimilation  of  carbon-dioxide,  5. 
Association   of  weeds  with  all  crops, 
162-4. 

cereals,  172-4. 

peas  and  beans,  162,  170, 

171. 

root  crops,  162,  164. 

"  seeds,"  162,  166-8. 

Aster  tripolium,  118. 
Atriplex  patula.     See  Orache. 
Australia,  4,  n,  43,  59,  no. 
Avenafatua.     See  Wild  Oat. 
A.flavescenSy  27. 
A.  strigosa,  12. 
Avens,  26,  194. 
Awn,  hygroscopic,  25,  188. 


BALLAST,  weeds  distributed  by,  10,  12. 
Barberry,  70. 

Barley,  5,  6,  7,  51,  57,  59,  99,  101  (fig.), 
115,  161-74. 

—  meadow,  178. 

—  wall,  27. 

—  wild,  112. 

Barn  field,  Rothamsted,  9. 

Bartsia  odontites.     See  Red  Bartsia. 

Bartsia,  red,  91,  93,  102  (fig.)>  148,  149, 

150,  156,  165,  174. 
Basic  slag,  69,  99. 
Bastard-alkanet,  195. 
Battlefield,  Somme,  76. 
Beans,  58,  161-74. 
Bedstraw,  94. 

—  ladies'.     See  Galium  verum. 

—  marsh,  178. 
Belgium,  112. 

Bellis  perennis.     See  Daisy. 


229 


230 


WEEDS  OF  FARM  LAND 


Bent,  black,  7,   8   (fig.),  52,  120,  134, 

135,    153,   156,    170,   171,   174,   207. 

See    also    A  tope  fur  us    agrestis    and 

Slender  Foxtail. 
Bent-grass,  38,  88,  126,  127,  151,  156, 

169,  174,  176,  179,  190,  206. 
Biennial  weeds,  58,  85,  no. 
Bilberry,  195. 

Bindweed,  n,  29  (fig.),  3*,  36,  70,  71, 
75,  89,   104,  136,   137,  153,   156, 

162,  163,  176,  178,  193,  212. 

—  black,  n,  31,  62,  89,  in,  123,  126, 

127,  151,  152,  157,  169,  170,  173, 
197,  220. 

—  greater,  73. 

Birds,  weeds  distributed  by,  28. 

Bisulphate  of  sodium,  60. 

Bittersweet,  31,  223. 

Blue  bur,  n. 

Boggy  soil,  117. 

Bone  meal,  69. 

Borage,  190,  208. 

Borago  officinalis,  190,  208. 

Botanical  analysis,  176. 

Brachypodium  pinnatum,  63,  69,    178, 

179. 

B.  sylvaticum,  63,  69,  178,  179. 
Bracken,  64,  65,  67,  104,  181,  198. 
Brassica,  11,  20,  75,  82. 
B.  alba,  139,  146,  147,  156,  165,  209. 
B.  campestris,  56,  128,  209. 
B.  sinapis,  56,  76,  136,  139,  147,  151, 

156,  162,  163,  173,  209. 
Bread,  191,  198,  199,  201. 
British  Association,  11. 
Briza  media,  179,  180  (fig.),  209. 
Broadbalk  field,  Rothamsted,  7,  9,  52, 

138,  140. 
Brome,  112. 

—  false,  63,  69,  178,  179. 

—  field,  182,  185,  209. 

—  rough,  178. 

—  soft,  44,  178,  179. 

—  sterile,  27.    See  also  Bromus  sterilis. 
Bromus  arvensis,   185,  209.     See  also 

Field  Brome. 

B.  asper,  209.     See  also  Rough  Brome. 
B.  mollis,  44,  178,  179,  209. 
B.  secalinus,  209. 
B.  sterilis,  27,  186,  209. 
Broom,  64. 

Broomrape,  20,  70,  79,  91,  93,  96  (fig.). 
98,  99,  104,  in,  218. 

—  branched,  97. 

—  eradication,  98. 

—  lesser.     See  Orobanche  minor. 
Bryonia  dioica,  73. 

Bryony,  white,  73. 

Bugloss,  small,  150,  157,  216. 

Bulb,  38,  86,  90. 


Bulbils,  39,  53. 
Bullocks,  75. 
Burdock,  73. 

Burial,  means  of  seed,  77. 
Buried  seeds,  64,  76,  78-83,  95,  97,  140. 
Burnet,  salad,  54,  178,  181,  198,  220. 
Buttercup,    3,    4,   16,    26,    31,  66,   104, 
105,  115,  178,  221. 

—  bulbous,  37  (fig.),  38,  87,  129,  177, 

185. 

—  corn,  25,  26  (fig.),  27  (fig.),  57,  58, 

87,  116,  120,  134,  135,  153,   158, 

170,  174,  221. 

—  creeping,    18,  28,  38,  40  (fig.),  88, 

126,  128,  151,  158,  165,  176,  187. 

—  tall,  148,  149;  150,    158,    177,  185, 

199. 


CABBAGE,  field,  128. 
Calamintha  acinos,  209. 
Calcifuge,  127. 
Calcium  carbonate,  118,  119. 

—  cyanamide,  60,  61. 
Calves,  105. 

Camelina  sativa,  191,  210. 
Campanula  corn,  150,  157,  215. 
Campion,  bladder,  70,  73,  148,  158,  171, 
174,  201,  223. 

—  reJ,  128,  216. 

-  white,  147,  148,  149,  153,  157,  159, 

165,  167,  216. 
Canada,  4,  n,  12,  43,  107,  116,  189. 
Capsella     bursa-pastoris.      See     Shep- 
herd's Purse. 
Caraway,  73. 
Carbolineum,  62. 
Cardamine  pratensis,  210.     See  Lady's 

Smock. 
Car  duns  nutans,  23,  150,  156,  167,  179, 

210. 

Car  ex,  179,  190,  210. 
C.  glauca,  210. 
C.  Jtirta,  210. 
C.  vulpina,  210. 
Cargoes,  weeds  distributed  by,   10,  n, 

12. 

Carr  land,  151. 
Carrot,  wild,  25,  26  (fig.),  44,  58,  73, 

86,  147,  148,  156,  167,  179,  212. 
Cart  tracks,  weed  flora  of,  16,  183. 
Cantm  carvi,  73. 
Catmint,  73. 

Cat's  ear,  104,  151,  179,  186,  215. 
Cat's  tail,   16.     See  also   Phleum  pra- 

tense. 
Cattle    (and   cows),    74,    75,  104,    107, 

108,  no,  in,  186,  187-205. 
Caucalis,  knotted,  128. 
Caucalis  nodosa,  128,  210. 


GENERAL  INDEX 


231 


Centaurea  nigra,  149.  See  also  Hard- 
head. 

C.  scabiosa.     See  Greater  Knapweed. 

Cerastium  vulgatum.  See  Mouse-ear 
Chickweed. 

Cereal  crops,  54,  62,  99,  159-74. 

Chalk,  intolerance  of,  132,  133. 

—  land,  weeds  of,  124,  146. 

—  manuring,  51. 

—  soil,  117,  122,  127. 
Chamomile,   16,  74,  76,    87,  115,   131, 

132,  157,  217. 

—  corn,  62,  129,  130,   151,    156,    167, 

207. 
Characteristic    weeds,    123,    134,    135, 

141,  146,  153. 
Charlock,  4,  n,  16,  17,  20,  28,  56,  57, 

58,  59,  60,  61,  62,  70,  76,  81,  82,  83, 

85,  87,  95,  104,  115,   136,  139,  146, 

147,    151,    156,    160,    162,  163,    173. 

See  Brassica  spp. 
Chemical    means,    eradication   by,   45, 

54-63,  66-70. 

Chenopodium  album.     See  Fat  Hen. 
Chervil,  wild,  17,  46,  64,  176,   179,  185, 

207. 

Chickweed,  4,  9,  18,  19,  28,  31,  46,  62, 
85,  87,  112,  123,  126,    127,    151, 

158,  169,   183,  2OI,  224. 

—  mouse-ear,  16,  17,  19,  28,  87,  126, 

128,  156,  165,  168,  174,  181,  183, 

211. 

Chicory,  54,  117,  igr,  211. 

Chloride  of  lime,  62. 

Chrysanthemum     leucanthemum.       See 

Dog  Daisy. 

C.  segetum.     See  Corn  Marigold. 
Cichorium  intybus.     See  Chicgry. 
Cicuta  virosa.     See  Cowbane. 
Cicutin,  in. 

Cinquefoil,  creeping,  38,  129,   198,  220. 
Circcea  lutetiana,  27. 
Cirsium  acaule,  65,  211. 
C.  arvense,  36,  179.    See  also  Creeping 

Thistle. 
C.  lanceolatum,  23, 179.    See  also  Spear 

Thistle. 

C.  palustre.     See  Marsh  Thistle. 
Classification  of  soils,  122. 
Ciay,  117,  120,  122,  127,  129. 
Cleaning  crops,  49,  161. 
Cleavers,    52,  85,  116,    153,   157.     See 

also  Goosegrass. 
Climbing  weeds,  89. 
Clover,  6,  50,  51,  53,  5  4,  55,  67,  75,  9 
93,  95,  96,  98,  in,  159,  166. 

—  suckling,  44. 

—  sweet,  ii,  104.     See  also  Melilotus. 
Cocksfoot-,  26,  182,  185,  186. 

Coffee  substitutes,  189,  191,  193,  202. 


Colchicine,  108. 
lolchicnm  autumnale,  38,  91,  107,  109 

(fig.),    178,     192,     212.       See    also 

Autumn  Crocus  and  Meadow  Saffron. 
Colonisation  of  dumps  by  weeds,  12. 
Coltsfoot,  18,  23,  24  (fig.),  34  (fig.),  37, 

53,  89,  120,  136,  137,  138,  158,  165, 

166,  202,  225. 
Competition,  aerial,  6,  50,  159. 

—  between  plants,  5,  68,  117,  118,  119, 

120,  127,  132,  159,  160,  166.  174, 

181. 
-  root,  6. 
Compost  heap,  48. 
Coniine,  106,  192. 

ionium  maculatum.     See  Hemlock. 
Conopodium  denudatum.     See  Pignut. 
Continuous  cropping,  effect  of,  7,  9. 
Convolvulus,  75T 
C.  arvensis.     See  Bindweed. 

major,  73. 
Copper  sulphate,  55,  56,  57,  59,  67. 

orm,  38. 
Corn  cockle,  4,  11,  104,  105,  106,  126, 

157,  186,  216. 

—  gromwell,  146,  147,  157,  195,  216. 

—  salad,  narrow  fruited,  73. 
Cornflower,  58,  62. 
Cosmopolitan  weeds,  4,  128. 
Cotton-grass,  177. 

ouch  grass,  16,  17,  32  (fig.),  36,  48, 
50,  53,  88,  120,  127,  136,  138,  156, 
169,  174,  176,  179,  189,  206. 

—  onion,  39,  41  (fig.),  90,  208. 
Cowbane,    104,  no.     See   also  Water 

Hemlock. 
Cowslip.  181,  220. 

ow-wheat,  93,  112. 

Crane's-bill,  20,  214.     See  also  Geran- 
ium. 

—  small-flowered,  150,  157,  167. 

—  soft   or  dove's  foot,  129,    130,  157, 

167,  172,  173,  174,  183,  214. 
Creeping  jenny,  178,  217. 

—  weeds,  88. 
Crepis,  23. 

C.  taraxacifolia,  178,  212. 

C.  virens,  97,  212. 

Crocus,  autumn,  104.     See  also  Colchi 

cum  autumnale. 
Cudweed,  23,  150,  156,  167,  213. 
-  marsh,  141,  146,  157,  214. 
Cultivation,  weeds  of,  10. 
Cumarin,  115. 
Cuscuta.     See  Dodder. 
C.  arvensis,  95. 
C.  epilinum,  94. 
C.  epithymum,  94. 
C.  europaa,  94,  212. 
C.  gronovii,  95. 


232 


WEEDS  OF  FARM  LAND 


C.  trifolii,  93  (fig.),  94,  95,  212. 
Cutting,   eradication   of  weeds  by,  64, 
65. 


Dactylis  glower  ata.     See  Cocksfoot. 
Daffodil,  181. 

Daisy,  16,  28,  88,  128,  178,  181,  183, 
208. 

—  dog  or  ox-eye,  63,  68,  115,  128,  178, 

179,  186,  211. 

Dandelion,  16,  23,  24  (fig.),  26,  28,  67, 

88,  148,  149,  151,  158,  171,  179,  185, 

201,  224. 

Darnel,  n,  104,  112,  114,  115,  216. 
Daucus   carota,   97.       See  also   Wild 

Carrot. 

Dead-nettle,  red,  87, 131,  132,  157,  169, 
215. 

—  white,  188. 

Destruction  of  weed  seedlings,  3. 
Digitalis  prtrpurea,  97. 
Discouragement  of  weeds  by  peas  and 

beans,  162,  171,  172. 
root  crops,  162,  165,  166. 

—  . •  "seeds,'   162,  168. 

Diseases,  fungus,  70. 
Distributed  weeds,  122. 
Distribution  of  weeds,  10,  152. 

Dock,  4,  21,  26,  28,  43,  44,  45,  46,  48, 
69,  88,  95,  176,  177,  179.  See 
also  Rumex  spp. 

—  blood-red.     See  Rumex  sanguineus. 

—  broad-leaved,  16,  22  (fig.),  73,  131, 

133,  158,  177,  183,  185,  200.     See 
also  Rumex  obtusifolius. 

—  curled,  47,  123,  126,  127,  151,  158, 

162,    163,    164,    222.      See   also 
Rumex  crispus. 

—  sharp,    177,  185.     See  also  Rumex 

conglomeratus. 

Dodder,  4,  20,  59,  75,  91,  93  (fig.),  94, 
95,  96,  99,  104,  179. 

—  clover,  93,  94,  95,  96. 

—  eradication  of,  95. 

—  flax,  93. 

—  lesser,  94. 
Dog's  mercury,  95. 
Dog's-tail,  182. 
Dominant  weeds,  122. 
Dominions,  43,  in,  115. 
Drainage,  107,  177,  181. 
Dry  storage  of  seeds,  73. 
Duration  of  weeds,  84. 

"  Dutch  Pink,"  188. 
" —  rushes,"  193. 
Dyer's  Rocket,  188. 

—  weed,  112. 

Dyes,    188,    189,    194,    195,    197,    199, 
204. 


Echium  vulgare,  212.  See  also  Viper's 
Bu  gloss. 

Elliott's  mixture,  53,  54,  191. 

Epilobium,  23,  25  (fig.). 

E.  angustifolium ,  76.  See  also  Fire- 
weed. 

E.  hirsutum,  212. 

Equisetum,  106,  107,  178,  213.  See 
also  Horsetail. 

E.  arvense,  107.     See  also  Horsetail. 

E.  hyemale,  193. 

E.  palustre,  66,  107. 

Eradication  of  weeds,  45,  71. 

Erect  weeds,  86. 

Erigeron  canadense,  213. 

Erodium  cicutarium,  213. 

E.  spp  ,  20,  213. 

Erysimum  cheiranthoides,  213. 

Euphorbia.     See  Spurge. 

E.  exigua,  152.  See  also  Dwarf 
Spurge. 

E.  helioscopia.     See  Sun  Spurge. 

E.  peplus.     See  Petty  Spurge. 

Ettphrasia,  93. 

E.  officinalis.     See  Eyebright. 

Eyebright,  93,  179,  213. 

FAIRY  rings,  181,  182. 

Fallowing,  52,  102. 

Farm  implements,  weeds  distributed  by, 

15,  45- 

Fat  hen,  12,  13  (fig.),  16,  31,  48,  74, 
75,  85,  87,  173,  126,  127,  140,  151, 
152,  156,  169,  173,  174,  183,  190, 

211. 

"  Fatting  "  pasture,  176. 

Feeding  value,  175,  176,  177,  179. 

Fen  land,  151. 

Fescue,  tall,  27. 

Festuca  elatior,  27. 

Fibre,  190,  203,  204. 

Filago  germanica.     See  Cudweed. 

Fireweed,  76,  83. 

Flax,  94. 

—  purging,  104,  108,  109    (fig.),    176, 

178,  216. 

Flour  substitutes,  189,  191,  201. 
Fodder,  189,  190,  191,  193,  198,   201, 

202,  204. 

Fool's  parsley,  17. 
Forget-me-not,  17,  27,   122,   126,    128, 

157,  168,  174,  217. 
Foxtail,  27,  75,  185,  186. 

—  slender,    16.     See   also  Alopecurus 

agrestis. 
France,  51,  60,  115. 
Frequency  of  occurrence,  122,  124. 

—  percentage  of,  125,  161. 
Fritillaria  meleagris,  181. 
Fritillary,  181. 


GENERAL  INDEX 


233 


Fruits  and  seeds,  weeds  distributed  by, 

18. 

Fumaria  officinalis.     See  Fumitory. 
Fumitory,  62,  85,  147,  148,  149,   156, 

171,  193,  213. 
Fungi,  181,  182. 
Fungus  diseases,  70. 

Galeopsis  tetrahit,  151,  213. 

Galium  aparine,  213.  See  also  Goose- 
grass  and  Cleavers. 

G.  tricorne,  214. 

G.  verum,  181,  188,  194,  214. 

Garlic,  3,  112,  113  (fig.),  114,  115,  176, 
178,  207.  See  also  Wild  Onion. 

Gas  lime,  69. 

Geese,  105, 187-205. 

General  occurrence,  weeds  of,  123,  124. 

Genista  tinctoria.     See  Woodwax. 

Geranium,  20,  214.  See  also  Crane's- 
bill. 

Geranium,  21,  87,  159.  See  also 
Crane's-bill. 

—  cut-leaved,  134,  153,  157,  167. 
Geranium   dissectum,    214.      See    also 

Cut-leaved  Geranium. 

G.  molle,  ii.  See  also  Soft  Crane's- 
bill. 

G.  pratense,  214. 

G.  pusillum,  150,  157,  167,  214. 

G.  robertianum,  n. 

G.  sylvaticum,  65. 

Geranium,  wood,  65. 

Germany,  68,  107. 

Germination  of  weed  seeds,  3,  7,  14, 

47,  72,  74,  83,  94.  97- 
Geum,  116. 
G.  urbanum,  26,  194. 
Githagin,  105. 
Glanx  maritima,  118. 
Gnaphalium     uliginosum,     23.        See 

Marsh  Cudweed. 
Goats,  106,  108,  187-205. 
Goatsbeard,  23,  24  (fig.),  181,  224. 
Gold-of-pleasure,  190,  210. 
Goosegrass,  25,    26  (fig.),  27,  28,  31, 

90, 136,  138,  169,  174,  193,  214.     See 

also  Cleavers. 

Gorse,  4,  71,  73,  78,  93,  202. 
Grass-land  weeds,  definition  of,  2,  176. 

eradication  of,  63-70. 

Grazing,  eradication  of  weeds  by,  63, 
64. 

—  with  cattle,  63,  64. 
geese,  64. 

sheep,  63,  64,  102,  no. 

Ground  ivy,  104,  129,  195,  217. 
Groundsel,  9,  16,  23,  24  (fig.),  28,  62, 

85,  87,  126,  127,  151,  158,  162,  163, 

164,  183,  200,  223. 


HABITS  of  growth  of  weeds,  86. 
Hardhead,  23,  63,  146,  147,  156,  171, 

178,  179,  2IO. 

Hawaii,  59. 

Hawkbit,  16,  23,  24  (fig.),  70.  See 
also  Leontodon  spp. 

—  autumnal,  17,  215. 
Hawk's-beard,  23 

—  beaked,  178,  212. 

Hawkweed,  mouse-ear,  23,  38,  39  (fig.), 

176,  181,  215. 
Heath,  78,  94. 
Heating  in  stack,  go. 
Heavy  land,  weeds  of,  123,  134. 
Hemlock,  4,  46,  73,  86,  104,  106,  176, 

187,  ig2,  212. 

—  water,  104,  no,  in. 
Hemp,  97. 

Henbit,  150,  157,  215. 

Heracleum  sphondylium.  See  Hog- 
weed. 

Hieracium  pilosella.  See  Mouse-ear 
Hawkweed. 

Hippocrepis  comosa,  17. 

Hogweed,  21,  22  (fig.),  27,  112,  147, 
148,  149,  157,  179,  182,  194,  214. 

Holcus  lanatus.     See  Yorkshire  Fog. 

Holland,  190. 

Hooked  fruits,  25,  115. 

Hoos  field,  Rothamsted,  7. 

Hordeum  murinum,  27. 

H.  pratense,  178,  215. 

Horses,  74,  75,  104,  105,  107,  108,  no, 
in,  186,  187,  204. 

Horsetail,  31  (fig.),  36,  89,  104,  106, 
136,  140,  151,  153,  156,  169,  193, 
213.  See  also  Equisetum  spp. 

—  field,    106,    107,    178.      See    also 

Equisetum  spp. 

—  marsh,  66,  107. 
Huffcaps,  112,  178,  205. 

Human  beings,  weeds  distributed  by, 

23,  26. 

Hygroscopic  awn,  25,  188. 
Hy peri  cum  hirsutum,  73. 
Hypoch&ris    radicata,   97.      See    also 

Cat's  Ear. 

IMPURE  seed,  transport,  10. 

India,  75. 

Insect  pests,  70,  71. 

Ireland,  43. 

Iron  sulphate,  55,  57,  58,  59,  6l»  67>  9^. 

Isatis  tinctoria,  194. 

Isle  of  Man,  43. 

Italy,  70. 

Ivraie,  115. 

Juncus.     See  Rush, 
y.  articulatus,  215. 


234 


WEEDS  OF  FARM  LAND 


y.  bufonius.     See  Toad  Rush. 
y.  communis,  215. 
y.  glaucits,  215. 

KAINIT,  60,  61,  62,  68. 
"  Kendal  green,"  194. 
Knapweed,  greater,  23,  147,  148,  156, 

211. 
Knawel,  annual,  87,  120,  141,  142,  143 

(fig.),  158,  200,  223. 
Knotgrass,  16,  19  (fig.),  28,  31,  48,  53, 

81,  87,  95,  124,  126,   127,  151,  157, 

16^,  170,  183,  197,  219. 

LADY'S  mantle,  87,  131,  132,  153,  156, 
168,  172,  174,  178,  207. 

—  smock,  178,  210. 

Lamium  amplexicaule,  150,  157,  215. 
L.  ptirpuretim.     See  Red  Dead-nettle. 
Lappula  echinata,  n. 
Lapsana  communis.     See  Nipplewort. 
Lathyrus  macrorrhizus,  215. 
L.  pratensis,  215. 
Lawns,  67,  182. 
Laying  down  to  grass,  52,  53. 
Legislation,  weed,  43,  44,  94. 
Legousia  hybrida,  150,  157,  215. 
Leontodon.     See  Hawkbit. 
L.  autumnalis,  17,  215. 
L.  hispidus,  215.     See  also  Hawkbit. 
Lettuce,  lamb's,  146,  147,  158,  225. 
-  wild,  95. 
Ley,  87,  166. 

Light  land,  weeds  of,  124,  141. 
Lime,  61,  62,  68,  69,  98,  118,  119,  141. 

—  nitrogen,  60,  61. 

—  requirement,  119. 

—  soils  deficient  in,  62,  69,  118,  145. 
L inaria  elatine,  215. 

L.  minor,  215. 

L.  spuria,  215.     See  also  Round-leaved 

Toadflax. 

L.  vulgaris.     See  Toadflax. 
Linum  catkarticum.    See  Purging  Flax. 
Lithospernum     arvense.        See     Corn 

Gromwell. 
Loam,  117,  122. 

—  heavy,  122,  129. 
—  light,  122. 

Lodging  of  cerea's,  89. 

Lolittm  temulentum.     See  Darnel. 

Longevity  of  seeds,  73. 

Loosestrife,  purple,  178. 

Lotus  corniculattis,  17,  97. 

Lousewort,  179. 

Lucerne,  50,  95,  96,  98.     See  also  Al- 

fal.fa. 
Lupin,  58. 

Luzula  carnpestris,  216. 
Lychnis  alba  =  L.  vespertina,  216. 


^.  dioica,  128,  216. 

'^.flos-cuculi.     See  Ragged  Robin. 

~  .  githago.     See  Corn  Cockle. 

r^.  vespertina.     See  White  Campion. 

,ycopsis  arvensis,  150,  157,  216. 

.ysimachia  nummularia.     See  Creep- 
ing Jenny. 

VlADDER,  field,  126,  128,  158,  159,  167, 

174,  223. 
Manure  heap,  weeds  of,  48,  183. 

—  weed  seeds  in,  75. 

— •  weeds  distributed  by,  12,  49,  75. 
Manures  and  Manuring,  9,  48,  54,  55, 

60,  62,  66,  68,  98,  182,  189,  191,  193, 

198,  201,  203. 
Marigold,  corn,  51,   87,   117,  141,    145 
(fig.),  156,  211. 

—  marsh,  178. 
Marsh  plants,  178. 

Matricaria  chamomilla.     See  Chamo- 

mile. 

M.  inodora.     See  Mayweeds. 
Mayweed,  16,  31,  62,  74,  87,  95,  104, 
115,  132,  183,  187. 

—  scentless,  131,  132,  151,    157,   165, 

174,  217. 

—  stinking,  134,  156. 
Meadow-grass,    annual,    87,    131,   132, 

151,  157,  169,  170,  174,  183,  219. 

—  rough-stalked,  182,  183,   184  (fig.), 

185. 

—  smooth-stalked,  185. 
Meadowsweet,  177,  224. 
Mechanical  means,  eradication  of  weeds 

by,  45.  46-54*  63-6. 
Medicago,  n,  58.     See  also  Medick. 
M.  lupulina,  74,  97,  217. 
M.  sativa,  97. 
Medicinal  uses  of  weeds,  187,  188,  189, 

191,  192, 193,  194,  195,  196,  200,  201, 

202. 

Medick,  58,  166.     See  also  Medicago. 

—  black.     See  Medicago  lupulina. 
Melampyrum,  93,  112. 

Melilot,  112,  115. 

Melilotus,  112,  115. 

M.  officinalis,  217. 

Mentha  aquatica,  217. 

M.  arvensis.     See  Corn  Mint. 

Mercnrialis  perennis,  95. 

Mignonette,  wild,  124,  146,  147,    158, 

167,  188,  221. 
Migration  of  weeds,  43. 
Milk,  tainting  of,  112,  113,  114,  115. 
Milkwort,  178,  219. 
Mint,  178. 

—  corn,  88,  136,  140,  157,  169,  217. 
Mixen-weed,  48. 

Moisture,  weeds  distributed  by,  15,  16. 


GENERAL  INDEX 


235 


Morning  glory,  75. 

Moss,  69,  70. 

Mosses,  181. 

Muck-weed,  48. 

Mud,  weeds  distributed  by,  15,  16. 

Mullein,  great,  73. 

Mustard,  50,  75,  115. 

—  ball,  ii. 

—  hedge,  129,  223. 

—  mithridate,     17,    224.       See     also 

Thlaspi  avveme. 

—  white,  123,  139,  146,  147,  156,  165. 
Mycelium,  182. 

Myosotis  arvensis.     See  Forget-me-not. 
M .  palustris,  217. 
M.  versicolor,  217. 
Myosurus  minimus,  217. 

Narcissus  pseudo-narcissiis,  181. 
Nepeta  cataria,  73. 
N.  glechoma,  129,  195,  217. 
Neslia  paniculata,  11. 
Nettle,  hemp,  151,  213. 

-  small,  141,  143,  153,  158,  225. 

-  stinging,  46,  62,  64,  65,  66,  68,  88, 

94,    95,  129,    176,  179,  185,   186, 

188,  194,  203,  225. 
New  Zealand,  n,  70,  no. 
Nickel  sulphate,  59,  60. 
Nightshade,  black,  31,  95,  in,  224. 

—  enchanter's  26. 
Nipplewort,  87,  136,  140,  157,  215. 

OAT,  tall,  27,  42,  176. 

—  wild,  4,  12,  15,   16  (fig.),  25,  51,  58, 

71,  188,  208. 

—  yellow,  27. 

Oats,  n,  50, 57,  59, 61,  78, 100,  112,  161- 

74- 

Occasional  weeds,  122. 

(Enanthe  crocata,  73. 

CE.  pimpinelloides,  217. 

Oil,  190. 

Onion,  wild,  17,  18,  38,  39,  53,  58,  91. 
See  also  Garlic. 

Ononis  repens  =  O. arvensis,  18, 179,217. 

Orache,  12,  14  (fig.),  62,  81,  87,  136, 
140,  151,  156,  169,  183,  188,  208. 

Orchard  grass,  186.  See  also  Cocks- 
foot. 

Orchis,  early.     See  Orchis  mascula. 

Orchis  maculata,  218. 

O.  mascula,  195,  196,  218. 

O.  morio,  218. 

Ornithogalum  pyrenaicum,  38,  91,  196, 
218. 

Ornithopus  perpusillus,  218. 

Orobanche.     See  Broomrape. 

O.  major,  218. 

O.  minor,  96,  97,  in. 


0.  ramosa,  97. 
Overcrowding,  effect  of,  5,  6. 

'  PANAISIE,"  112. 
Pansy,  field,  31,  87,  147,  148,  149,  151 

152,  158,  165,  167,  226. 
Papaver  argemone,  131,  133,  157,  218. 
P.  dubium,  128,  218. 
P.  hybridum,  219. 
P.  rhceas.     See  Poppy. 
Paper-making,  189. 
Pappus,  23. 

Parasites,  eradicat  on  of  weeds  by,  70. 
Parasitic  weeds,  91,  92-102,  179. 
Parsley,  fool's,  73,  104,  106,  128,  2o5. 
Pasture,  calcareous,  64. 

—  down,  63,  69. 

-  old,  2,  76,  77,  79. 
Pea,  wild,  71. 
Peas,  48,  58,  161-74. 
Peat,  122,  144,  177. 

—  soils,  weeds  of,  124,  150. 
Pedicularis,  93. 

P.  palustris,  179. 
P.  sylvatica,  219. 
Pennycress,  115.  See  also  Thlaspi 

arvense. 

Pennywort,  178. 
Perennial  weeds,  46,  86,  88. 
Persecaria,  17,  31,  62,  104.     See   also 

Willow-weed. 
Pests,  insect,  70,  71. 
Pheasant  crops,  weed  seeds  in,  29. 
Phleum  pratense,  75.     See  also  Cat's- 

tail. 

Physiological  conditions  in  soil,  83. 
Pig,  74,  105,  108,  187-205. 
Pignut,  38,  87,  178,  181,  185,  186,  192, 

193,  212. 
Pigweed,  75. 
Pimpernel,  scarlet,  16,  19,  31,  73,  85, 

87,  104,  147,  148,  149,  156,  165,  173, 

187,  207. 

Pimpinella  saxifraga,  219. 
Plant  nutrition,  92,  94,  99. 
Plantago  coronopus,  219. 
P.  lanceolata.     See  Ribwort  Plantain. 
P.  major.     See  Greater  Plantain. 
P.  media.     See  Hoary  Plantain. 
Plantain,  31,  74,  88. 

—  greater,  9,  16,  88,  136,  157,  165,  173, 

181,  183,  184  (fig.),  197,  219. 

—  hoary,  73,  88,  94,  120,  134,  153,  157, 

181,  183,  197,  219. 

—  ribwort,  28,  74,  88,   123,    126,    127, 

157,  167,  172,  173,  181,  197,  219, 
Ploughing,  deep,  51. 

—  effect  of,  46. 

Plumed  fruits,  23,  24  (fig.). 

-  seeds,  23,  25  (fig.). 


WEEDS  OF  FARM  LAND 


Poa  annua.  See  Annual  Meadow- 
grass. 

P.  pratensis,  185. 

P.  trivialis.  See  Rough-stalked 
Meadow-grass. 

Poisonous  plants,  104-11,  176,  178. 

Poly  gala  vulgaris,  178,  219. 

Polygonum  aviculare.     See  Knotgrass. 

P.  convolvulus.     See  Black  Bindweed. 

P.  lapathijolium,  220. 

P.  persecaria.  See  Willow-weed  and 
Persecaria. 

Poor-man's  weather-glass,  149.  See 
Scarlet  Pimpernel. 

Poppy,  5,  16,  20,  45,  56,  58,  61,  62,  70, 
76,  81,  83,  85,  87,  104,  117,  128, 
129,  130,  153,  154,  157,  160,  165, 
173,  187,  196,  219. 

—  Destroyer,  47. 

-  pale,  131,  133,  157,  218. 

red,    128.       See    also    Papaver 

dubium. 

"  Poppyland,"  154. 
Pot  cultures,  118. 
Potash,  60,  199. 
Potassium  chloride,  60. 
Potatoes,  58. 

Potentilla  anserina.     See  Silverweed. 
P.  reptans.     See  Creeping  Cinquefoil. 
P.  tormentilla.     See  Tormentil. 
Poterium   sanguisorba,   97.      See   also 

Salad  Burnet. 
Poultry,  105,  187-205. 
Prairie  sunflower,  n. 
Prevention  of  weeds,  43-5. 
Primula  veris,  181,  220. 
Proclaimed  plants  (weeds),  4,  43. 
Prostrate  habit  of  grasses,  183,  185. 
Prunella  vulgaris,  129,  181,  220. 
Prussic  acid,  109. 
Pteris  aquilina.     See  Bracken. 
Puffballs,  182. 

QUAKER  Grass,  178,  179,  180  (fig.), 
209. 

RADISH,  wild,  48,  58,  60,  6r,  62,  85,  87, 

104,  126,  128,  158,  221. 
Ragged  Robin,  151,  177,  216. 
Ragwort,    16,  65,  104,    109,    no,  178, 
223. 

—  eradication  of,  no. 

Ramsons,  38,  112,  113  (fig.),  114,  178, 
190,  207. 

Ranunculus.     See  Buttercup. 

R.  acris,  26,  220.  See  also  Tall  Butter- 
cup. 

R.  arvensis.     See  Corn  Buttercup. 

R.  bulbosus,  26,  221.  See  also  Bulbous 
Buttercup. 


R.  hirsutus,  221. 

R.   repens,   221.       See  also   Creeping 

Buttercup. 
Rape,  52. 
Raphanus   raphanistrum.      See    Wild 

Radish. 

Rapi strum  rugosum,  n. 
Rattle,  red,  93. 

—  yellow,  18,  21,  22  (fig.),  64,  91,  93, 

98,  99,  100  (fig.),  101  (fig.),  102, 
104,  178,  179,  199,  222. 
Reproduction,  sexual,  18. 

—  vegetative,  18,  31,  86. 
Reseda,  112. 

R.  lutea.     See  Wild  Mignonette. 

R.  luteola,  188. 

Reserve  food,  85,  87,  97. 

Respiration,  5. 

Restharrow,  18,  179,  217. 

Rhinanthus   crista-galli.      See   Yellow 

Rattle. 

R.  major,  99,  roo  (fig.),  101  (fig.). 
jR.  minor,  98. 

Rhizomes,  88,  89,  no,  138,  189. 
Ribgrass,  2,  4,  182.     See  also  Ribwort 

Plantain. 
Root  crops,  6,  9,  49,  51,  58,  159,  161- 

74- 

Rose-bay,  76. 
Rosette  weeds,  88,  176. 
Rotation  of  crops,  6. 
Rothamsted,  7,  42,  52,  59,  74,  79,  82, 

118,  138,  139,  140,  152,  154. 
Rumex  acetosa,  144.     See  also  Sorrel. 
R.  acetosella.     See  Sheep's  Sorrel. 
R.  conglomeratus,   44,    222.     See  also 

Sharp  Dock. 
R.   crispus,    44,    69,     See   also   Curled 

Dock. 
R.  obtusifolius,  44,  69,  179,  183,  222. 

See  also  Broad-leaved  Dock. 
R.  sanguineus,  26,  177,  222. 
Running  grasses,  49. 
Rush,  66,  88,  177,  178,  170,  200,  215. 

—  toad,  20,  76,  183,  215. 
Russia,  11,  107. 

Rust,  70. 

Ryegrass,  16,  53,  54,  182,  185,  186. 

SAFFRON,  meadow,  108,  176,  187.  See 
also  Colchicum  autumnale,  and 
Autumn  Crocus. 

Sainfoin,  55,  96. 

St.  John's  wort,  hairy,  73. 

Salep,  196. 

Salicornia  spp.,  118. 

Salsify,  purple,  73. 

Salt,  67,  68,  99,  102,  118. 

—  marshes,  118. 

Sandy  land,  117,  120,  122,  141. 


GENERAL  INDEX 


237 


Sandwort,  31,  129,  130. 

—  thyme-leaved,  85,  156,  168, 174,  208. 
Scabiosa  arvensis.     See  Scabious. 

S.  succisa,  222. 

Scabious,  124,  148,  158,  171,  179,  222. 

Scale  leaves,  32. 

Scandix    pecten.         See      Shepherd's 

Needle. 

Scarce  weeds,  122. 
Scleranthus     annuus.        See     Annual 

Knawel. 

Scour,  107,  193. 
Scrambling  weeds,  89. 
Sedge,  178,  179,  190,  210. 
Seed  production,  abundant,  18,  77,  84. 

—  Testing  Station,  44. 
Seedlings,  destruction  of,  3. 

"  Seeds  "  crops,  6,  132,  161-74. 

Selfheal,  129,  181,  220. 

Senebiera  coronopus.     See  Swine-cress. 

Senecio  Jacob  cea.     See  Ragwort. 

S.  vulgaris.     See  Groundsel. 

Serradella,  55,  58. 

Serratula  tinctoria,  223. 

Sexual  reproduction,  18. 

Sheep,  107,  108,  no,  in,  116,  186, 
187-205. 

Sheep's  sorrel,  4,  18,  28,  36,  44,  49,  62, 
68,  69,  74,  104,  in,  118,  119,  120, 
141,  143,  144  (fig.),  151,  153,  154, 
158,  162,  163,  174,  179,  223. 

Shepherd's  needle,  25,  28  (fig.),  50, 
87,  126,  127,  153,  155,  158,  165, 
173,  223. 

—  purse,    4,  16,  17,  20,  85,   88,   no, 

112,  126,  127,  156,  162,  163,  164, 

183,  2IO. 

Sheradia  arvensis.     See  Field  Madder. 

Silage  crops,  50. 

Silene  anglica,  223. 

S.  inflata.     See  Bladder  Campion. 

S.  noctiflora,  223. 

Silverweed,  16,  38,  88,  104,  126,  128, 

151,  158,  171, 179,  183, 184  (fig.),  197, 

220. 

Sisymbrium  officinale,  129,  223. 
Smother  crops,  50,  51,  159,  166,  170. 
Sodium  arsenite,  59,  67,  96. 

—  bisulphate,  60. 
— nitrate,  96. 

Soils,  classification,  122. 

Solanum  dulcamara,  31,  223. 

S.  nigrtim,  31,  95,  in,  224. 

Somme  battlefield,  76. 

Sonchus  arvensis.  See  Corn  Sow- 
thistle. 

S.  oleraceus.     See  Sowthistle. 

Sorrel,  21,  36  (fig.),  38,  68,  104,  118, 
119,  178,  179,  182,  185,  186,  188,  199, 
222.  See  also  Rumex  acetosa. 


Sour  land,  141. 

Sowthistle,  23,  62,  70,  95,  201,  224. 

—  corn,  9,   18,  33  (fig.),  36,  48,  136, 

I5It  158,  162,  163,  164,  224. 
Speedwell,  19,  31,  62,  87. 

—  field,  16,  17,  81,  82,  122,  126,  127, 

J39,  158,  162,  163,  164,  173,  225. 

—  germander,  181,  225. 

—  ivy-leaved,   82,   85,   131,  158,    169, 

225. 

—  large  field,  136,  139,  158,  169,  170, 

225. 

—  thyme-leaved,  150,  158,  183,  225. 

—  wall,  131,  158,  168,  172,  174,  225. 
Spergula    arvensis,     154.       See     also 

Spurry. 

Spirceajilipendula,  224. 
S.  ulmaria.     See  Meadowsweet. 
«'  Splits,"  125. 
Spraying,  time  of,  56. 
Sprays,  9,  54,  55,  59,  66,  67,  96. 
Spurge,  20,  85,  87,  104,  in,  213. 
—  dwarf,  16,  136,  138,  156,  165,  213. 
See  also  Euphorbia  exigua. 

—  petty,  126,  128,  156,  213. 

—  sun,  129,   130,  156,   171,  174,  187, 

213. 

Spurry,  4,  16,  19,  21,  22  (fig.),  31,  56, 
62,  85,  87,  117,  120,  123,  141,  142 
(fig.),  151,  153,  158,  160,  169,  170, 
173,  174,  201,  224.  See  also  Spergula 
arvensis. 

Stocky  s  arvensis,  in,  224. 

S.  betonica,  224. 

S.  palustris,  224. 

Stagger  weed,  in. 

Star-of-Bethlehem,  spiked,  38,  196. 
See  also  Ornithogalum  pyrenaicum. 

Stellar ia  graminea,  224. 

S.  media,  130,  191.  See  also  Chick- 
weed. 

Stinkweed,  115.  See  also  Thlaspi 
arvense. 

Stitchwort,  187. 

Stork's-bill,  20,  213. 

Storm  columns,  weeds  distributed  by, 

Struggle  for  existence,  120. 
Suceda  fruticosa,  118. 
S.  maritima,  118. 
Sub-dominant  weeds,  122. 
Sulphate,  ammonium,  69. 
-  copper,  55,  56,  57,  59,  67. 

—  iron,  55,  57,  58,  59,  61,  67,  96. 

—  nickel,  59,  60. 
Sulphuric  acid,  55,  58,  60,  67. 
Superphosphate,  69. 
Survey,  weed,  121. 

Swine-cress,  16,  87,  136,  137,  158,  183, 
223. 


WEEDS  OF  FARM  LAND 


Switzerland,  108,  igi. 

Swollen  internodes,  weeds  with,  go. 

—  stems,  38. 

Symptomatic  weeds,  120,  134. 


TAINTING  of  milk,  112,  113,  114,  115. 
Taraxacum  vulgare.     See  Dandelion. 
Tares,  50,  114. 
Tarred  paper,  eradication  of  weeds  by, 

66. 

Tasmania,  weeds,  4. 
Tea  substitutes,  i8g,  ig4,  201. 
Temporary  grass,  162-74. 
Tendril,  go. 

"  Testing  of  Seeds  "  Order,  44. 
Thalecress,  I2g,  208. 
Thatch,  igo,  ig8. 

Thistle,  18,  36,  43,  45,  47,  48,  61,  64, 
65,  67,  68,  8g,  127,  176,  i7g. 

—  creeping,  4,  g,  16,  23,  24  (fig.),  30 

(fig.),  70,  82  (fig.),  95,  126,  127, 
156,  162,  163,  164,  183,  186,  211. 
-  marsh,  66,  86,  211. 

—  milk,  4. 

—  musk,    150,    156,    167.      See    also 

Carduus  nutans. 

—  spear,  86,  128,  167,  211. 

—  stemless,  65,  211. 
Thlaspi  arvense,  17,  115,  224. 
Threshing  machines,  15,  45. 
Thyme,  g4,  178. 

Timothy,  75. 

Toadflax,  21,  31,   146,  147,  153,   157, 

162,  163,  igs,  215. 
—  round-leaved,  147,  148,  150,  157. 
Toadstools,  182. 
Tomato,  g7. 
Tor  grass,  6g. 
Tormentil,  104,  ig8,  220. 
Tragopogon  porrifolius,  73. 
T.  pratensis.     See  Goat's- beard. 
Trailing  weeds,  87. 
Transport  of  impure  seed,  10. 

—  weeds  distributed  by,  10. 
Transvaal,  weeds,  43. 
Trefoil,  166. 

—  bird's-foot.     See  Lotus  corniculatus. 
Trifolium,  75. 

T.  angulatum,  44. 
T.  arvense,  gj. 
T.  dubium,  44. 
T.filiforme,  gj. 
T.  parviflorum,  44. 
T.  pratense,  g7,  ng. 
T.  procumbens,  44. 
T.  repens,  gj. 
T.  striatum,  gj. 
T.  strictum,  gj. 
T.  subterraneum,  gj. 


Triticum     repens — Agropyron     repens, 

225. 

Tuber,  38. 
Tufted  weeds,  87. 
Turnip  crop,  51. 

Tussilagofarfara.     See  Coltsfoot. 
Twitch,  47,  48,  4g,  127,  132. 

UBIQUITOUS  weeds,  123,  125. 
Ulex  europczus.     See  Gorse. 
Underground  stems,  g,  31,  46,  86,  88, 

104,  in. 

United  States,  4,  114. 
Urtica  dioica,  i2g,  i7g,  188,  ig4,  203, 

225.     See  Stinging  Nettle. 
U.  urens,  i7g.     See  also  Small  Nettle. 

Vaccinium  uliginosum,  ig5. 

Valerian,  common,  73. 

Valeriana  officinalis,  73. 

V.  dentata,  73. 

V.  olitoria,  146,  147,  158,  225. 

Vegetative  reproduction,  18,  31,  86. 

Verbascum  thapsus,  73. 

Vernal-grass,  182. 

Veronica  agrestis.  See  Field  Speed- 
well. 

V.  arvensis.     See  Wall  Speedwell. 

V.  chamcedrys.  See  Germander  Speed- 
well. 

V.  hedercefolia.  See  Ivy-leaved  Speed- 
well. 

V.  serpyllifolia.  See  Thyme-leaved 
Speedwell. 

V.  tournefortii,  81.  See  also  Large 
Field  Speedwell. 

Vetch,  common,  73. 

—  horse-shoe,  17. 

—  kidney,  187,  208. 

—  narrow-leaved,  21  (fig.),  226. 

—  tufted,  17,  18,  226. 

—  wild,  n,  20,   go.     See  also    Vicia 

sepium. 

Vetches,  50,  53,  58. 
Vetchling,  58. 

Vicia,  20.     See  also  Wild  Vetch. 
V.  angustifolia,  21  (fig.),  226. 
V.  cracca,  f7,  18,  226. 
V.  hirsuta,  226. 
V.  sativa,  73,  226. 
V.  sepium,  226. 
V.  tetrasperma,  226. 
Viola  tricolor.     See  Field  Pansy. 
Viper's  Bugloss,  104,  212. 

WATER  culture  experiments,  5. 
Watercress,  n,  178. 
Water  dropwort,  hemlock,  73. 
Water  grass,  47.     See  also  Agrostis. 

—  logging,  66,  118,  133,  177. 


GENERAL  INDEX 


239 


Water  plants,  178. 

Weed  communities,  117,  120,  124. 

—  flora,  introduced  or  alien,  4,  n. 

of  gateways,  16,  183. 

paths,  183. 

rick  sites,  185. 

—  shady  places,  177,  185,  186. 

trodden  places,  183,  184. 

Weeds  harmful  to  farm  products,  112- 

116. 
human  beings,  103-12. 

live  stock,  103-12. 

Wheat,  5,  6,  7,  52,  58,  70,    102,  105, 

112,  114,  160-74. 

Willow-herb,    23,  25    (fig.).     See   also 
Epilobium  spp. 


Willow-weed,  66,  70,  76,  117,  131,  133, 
I5I>  *57i  169,  188,  220.  See  also 
Persicaria. 

Wind,  weeds  distributed  by  17,  21. 

Winged  fruits,  21,  22  (fig.). 
-  seeds,  21,  22  (fig.),  99. 

Woad,  194. 

Woburn  Experimental  Station,  53. 

Woodwax,  35  (fig.),  37,  66,  115,  176, 
179,  188,  194,  214. 

YARROW,   17,   28,    115,  128,   151,  179, 

182,  188,  206. 

Yellow  Rattle,  eradication,  99. 
Yorkshire  Fog,  2,  27,  44,  176,  179,  185, 

215- 


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